On a recent survey, Stat 200 students were asked: How low must the temperature go (in degrees Fahrenheit) for you to stop wearing shorts when you are out
... [Show More] and about, such as going to class. It was also determined whether the student was a female or male. The goal is to compare the responses for the two genders.
In this instance, which is true about the two variables? - correct answer the explanatory variable is categorical and the response variable is quantitative
Which is untrue about the standard deviation? The standard deviation is _____
A) is an accurate measure of spread no matter what is the shape of the data.
B) only be fully interpreted when the empirical rule is applied
C) a sensitive measure of spread
D) roughly defined as the average distance of an observed value from the mean - correct answer A) is an accurate measure of spread no matter what the shape of the data is
A recent Gallup Poll found that 60% of all American adults enjoy saving money more than spending it. The results are based on telephone (both cell and landline) interviews with a random sample of 2,017 national adults, aged 18 and older.
Ideally: What is the population of interest to the Gallup Poll?
A) all American adults
B) all American adults who have telephones (cell and/or landlines)
C) all American adults who support "saving" over "spending"
D) 2,017 American adults who participated in the Gallup Poll - correct answer A) all American adults
A recent Gallup Poll found that 60% of all American adults enjoy saving money more than spending it. The results are based on telephone (both cell and landline) interviews with a random sample of 2,017 national adults, aged 18 and older. The data that is initially obtained from each adult is:
A) categorical
B) quantitative and discrete
C) quantitative and continuous - correct answer A) categorical
The typical number of hours/night spent sleeping when considering college students has a normal shape where the mean is 7 hours and the standard deviation is 1.2 hours.
About 99.7% of the hours/night spend sleeping fall within what boundaries? Identify the correct calculation.
A) 7 ± 1
B) 7 ± 2
C) 7 ± 3
D) 7 ± 2×(1.2)
E) 7 ± 3×(1.2) - correct answer E) 7 ± 3 x (1.2)
The distance (in miles) between where you live in State College and your home town/city
This random variable is ________:
A) discrete
B) continuous - correct answer B) continuous
This table summarizes resting heart rates (beats/minute) for 20 PSU female athletes :
Min Q1 Median Q3 Max
40 45 50 60 70
In this instance: which is the correct interpretation of the IQR? The variation in the _________
A) middle 50% of the data spans 15 beats/min
B) middle 50% of the data spans 5 beats/min
C) outer 50% of the data spans 15 beats/min
D) outer 50% of the data spans 5 beats/min - correct answer A) the middle 50% of the data spans 15 beats/minute
To test the stimulus effect of caffeine, a study took a sample of 14 students and randomly divided them into two equal groups such that each were given one of two possible doses of caffeine (100 mg, 200 mg). Two hours later, each student was asked to complete a tapping exercise. The response variable is: the number of taps/minute. The goal is to determine if the mean number of taps/minute is larger for those taking 200 mg.
This study is:
A) a randomized experiment where a cause and effect statement could be included
B) a randomized experiment where a cause and effect statement could not be included
C) an observational study where cause and effect statement could be included
D) an observational study where cause and effect statement could not be included - correct answer A) a randomized experiment where a cause and effect statement could not be concluded
This table summarizes amount of time (in hours/day) spent on the computer by 20 Stat 200 students
Min Q1 Median Q3 Max
1 3 4 6 10
Approximately what percent of the computer times lie above 6 hours/day?
A) 0%
B) 25%
C) 50%
D) 75%
E) 100% - correct answer B) 25%
Which would most likely be true when considering salaries in a medical practice company that employs: 2 entry-level nurses and 20 very highly paid doctors?
One would find _______
A) median > mean
B) mean > median
C) mean = median - correct answer A) median > mean
Match the statistical notation with the corresponding term.
A. μ
B. σ
C. p
D. s
E. x
sample standard deviation
sample mean
population mean
population standard deviation
population proportion for a success - correct answer sample standard deviation - s
sample mean - x
population mean - μ
population standard deviation - σ
population proportion - p
When comparing the chi-square statistic with the correlation, which is untrue?
Both:
A) are calculated using two variables of the same type
B) are predictably affected by sample size in the same way
C) have corresponding p-values
D) have the same value where there is no relationship or no linear relationship - correct answer B) are predictably affected by the sample size in the same way
Which is untrue is about a correlation? A correlation, when calculated, _____
A) is stripped of the original units of measurement found with the two variables
B) can either increase or decrease in strength when an outlier is present
C) does not needs to designate one variable as the explanatory variable and one variable as the response variable
D) is a resistant statistic
E) should only be compared to correlations that come from the same sample size - correct answer D) is a resistant statistic
When the Chi-Square statistic = 0: which is untrue?
A) two individual row percents (risks) are the same
B) p-value = 1.0
C) the odds are the same for the two groups
D) relative risk = 1
E) increased risk = 100%.
F) with each cell, actual count = expected count - correct answer E) increased risk = 100%
Consider 4 different (x, y) pairs found in the provided answers. Which pair, when removed, would lead to the other pairs to having a correlation of 1.0.
A) (10, 20)
B) (20, 30)
C) (25, 25)
D) (30, 40) - correct answer C) (25,25)
Which is untrue about a binomial distribution?
A) P(X>3) = P(X >= 4)
B) range of possible values are between: -3 to 3
C) can find exact probabilities
D) random variable is discrete - correct answer B) range of possible values are between -3 to 3
Match the name with the corresponding statistic. Use each answer only once.
A. individual risk
B. odds
C. relative risk
D. increased risk
1. A national poll finds that by 58% to 42% Americans believe that gun sales should be made "more" strict to "less" strict.
2. People who have a strong sweet tooth are 20% more likely to develop metabolic syndrome than those who do not have a strong sweet tooth.
3. One in Five US workers won't retire
4. Drinking at least 3 cups of coffee a day doubles the risk for gall bladder cancer. - correct answer 1. odds
2. increased risk
3. individual risk
4. relative risk
Match the values of n and p with the shape of the binomial distribution. Use each answer only once.
A. normal
B. positively (right) skewed
C. negatively (left) skewed
1. n = 8 & p = .1
2. n = 8 & p = .5
3. n = 8 & p = .7 - correct answer 1. right skewed
2. normal
3. left skewed
In a Stat 200 data set, the heights for all the female students was obtained. Also included were the heights of the mother, the father, and the mid-parent height (average height of two parents). These heights are possible explanatory variables from the female student height.
x = height (mother, father, or mid-parent height) - inches
y = female student height (inches)
The results from the Analysis of Variance tables for each possible explanatory variable are found below.
Possible Explanatory Variables
SSR SSE SSTO
Mother's Height 220 780 1000
Father's Height 350 650 1000
Mid-Parent Height 250 750 1000
Which explanatory variable does the best job of explaining the variation in the heights of the female students?
A) Mother's Height
B) Father's Height
C) Mid-Parent Height - correct answer B) Father's height
Which correlation shows the weakest linear relationship?
A) -.7
B) -.2
C) .1
D) .6 - correct answer C) .1
Which is untrue about a population parameter? A population parameter ______
A) has a value that may or may not be known once the population is defined.
B) has a corresponding sampling distribution
C) can only assume one value once the population is defined
D) is a number that describes a population - correct answer B) has a corresponding sampling distribution
A random sample of 500 students at a university with 15-week semesters was asked whether or not they think the semester should be shortened to 14 weeks (with longer classes). Sixty percent of the 500 students surveyed answered "yes."
The relevant minitab output is found below.
Sample X N Sample p 95% CI
1 300 500 0.600000 (0.556, 0.643)
Using the provided 95% confidence interval, which is the correct interpretation? We are 95% confident that the ____________
A) population proportion who prefer the 14-week semester is between .556 and .643.
B) sample proportion who prefer the 14-week semester is between .556 and .643.
C) population mean number who prefer the 14-week semester is between .556 and .643.
D) sample mean number who prefer the 14-week semester is between .556 and .643. - correct answer A) population proportion who prefer the 14-week semester is between .556 and .643
Gallup Poll: Oct 25, 2013. Fewer Americans today believe there is "plenty of opportunity" to get ahead in America than reported in previous polls. A recent poll found 52% of Americans say the country still has plenty of economic opportunity. This poll has a 4% margin of error at 95% confidence. Suppose this poll result was instead calculated at 98% confidence. Which would be true?
Statistically speaking: we can claim that a majority has been found:
A) at 95% confidence but not at 98% confidence
B) at 98% confidence but not at 95% confidence
C) at both 95% confidence and 98% confidence
D) at neither 95% confidence nor 98% confidence - correct answer D) at neither 95% confidence nor 98% confidence
It was supposed to be the American dream to own a home. According to the most recent decennial census, about 70% of Americans were found to be homeowners. However, in recent years it is believed that this percent has decreased. A recent sample of 100 adults, found 65 to be homeowners. Does the data suggest that percent is now less than 70%?
Below the the corresponding Minitab Output
Test of p = 0.7 vs p < 0.7
95% Upper
Sample X N Sample p Bound Z-Value P-Value
1 65 100 0.650000 0.728455 -1.09 0.138
Using the normal approximation.
Which is the correct interpretation of the test statistic? The:
A) (sample proportion of .65) is 1.09 standard deviations above the (population proportion of .70)
B) (sample proportion of .65) is 1.09 standard deviations below the (population proportion of .70)
C) (population proportion of .65) is 1.09 standard deviations above the (sample proportion of .70)
D) (population proportion of .65) is 1.09 standard deviations below the (sample proportion of .70) - correct answer B) (sample proportion of .65) is 1.09 standard deviations below the (population proportion of .70)
Determine which graph is appropriate for each pair of variables that come from a sample of PSU students. Each graph should only be used once.
A. side-side boxplots
B. scatterplot
C. two-dimensional bar graph
D. bar graph
E. histogram
1. whether or not the student has pulled an all-nighter) and (whether or not the student has taken recreational drugs)
2. (number of parties attend/month) and (amount of alcohol consumed in a month)
3. (amount of student debt) and (year in school: freshman, sophomore, junior, senior)
4. favorite sport: (football, basketball, baseball, soccer, other)
5. amount of money/month spent on a cell phone plan - correct answer 1. C
2. B
3. A
4. D
5. E
Health officials thought that they had started to get a handle on lead poisoning for children ages 1-5 years such that only 1 out of 72 children were now found to be at risk. However in the past year, because of budget cuts, the risk for lead poisoning has increased. Blood tests on 1,653 children aged 1-5 years have found 50 children to have blood levels above the acceptable threshold value. Does the data suggest that this risk has increased over the past year.
Which correctly states the hypotheses for a hypothesis test?
A) Ho: p = 50/1,653 & Ha: p > 50/1,653
B) Ho: p = 50/1,653 & Ha: p < 50/1,653
C) Ho: p = 1/72 & Ha: p > 1/72
D) Ho: p = 1/72 & Ha: p < 1/72 - correct answer C) Ho: p = 1/72 & Ha: p > 1/72
Consider a hypothesis test
Ho: p = .2 Ha: p > .2 Z-statistic = -1.74.
Which is the correct interpretation and possible value for the p-value?
The likelihood of obtaining a Z test statistic of -1.74:
A) or any value larger, if in fact the null hypothesis is true, is .9591.
B) or any value larger, if in fact the null hypothesis is true, is .0409.
C) or any value smaller, if in fact the null hypothesis is true, is .9591.
D) or any value smaller, if in fact the null hypothesis is true, is .0409 - correct answer A) or any value larger, if in fact the null hypothesis is true, is .9591
In a Stat 200 data set, the heights (in inches) of sudents is included. This data set also includes the mid-parent height (in inches). Below is Minitab output based on this data.
The regression equation is
Height = 4.7 + 0.94 midparent
Predictor Coef SE Coef T P
Constant 4.70 17.91 0.26 0.796
midparent 0.940 0.270 3.48 0.003
S = 3.18 R-Sq = _______
Analysis of Variance
Source DF SS MS F P
Regression 1 122.00 122.00 12.10 0.003
Residual Error 16 162.00 10.10
Total 17 284.00
When using the provided output, which is untrue? We can say that:
A) the average value for a residual is 3.18 inches
B) if the correlation test were done, statistical significance would be found
C) for every one inch increase in height found with the mid-parent, one can expect the student's height to increase by .94 inches, on the average
D) the sample slope of .940 is 3.48 standard deviations above the null value where the population slope = 0.
E) the squared correlation > 50% - correct answer E) the squared correlation > 50%
Match the confidence interval for the population proportion with the corresponding level of confidence. Each interval is based on the same value for the 1) sample proportion & 2) n.
A. 90%
B. 95%
C. 99%
C.I. for population proportion: (.1 to .9)
C.I. for population proportion: (.3 to .7)
C.I. for population proportion: (.4 to .6) - correct answer 1. C
2. B
3. A
Ho: p=.20 & Ha: p > .20 Z=5.59
Which is the correct p-value for this hypothesis test?
A) 0
B) .2000
C) .5000
D) 1.0 - correct answer A) 0
Z is a standard normal random variable. Consider the probability statement: P(-2.4 < Z < 2.3). Which is a possible probability for this statement? Select closest number
A) .6800
B) .8224
C) .9500
D) .9811
E) .9970 - correct answer D) .9811
A recent poll of 1,012 Americans found that only 33% believe that people are generally trustworthy. Your goal is to estimate the population percent of all Americans who believe that people are in general trustworthy.
The correct population parameter and inferential procedure in this instance are:
A) one population proportion: confidence interval
B) one population proportion: hypothesis test
C) one population mean: confidence interval
D) one population mean: hypothesis test
E) population mean difference: hypothesis test - correct answer A) one population proportion: confidence interval
When considering all people who work in the U.S., what is the average number of hours/week spent working? A sample of 12 people who currently work was obtained. Each person was asked how many hours/week do you work.
Below are the results from Minitab.
N Mean StDev SE Mean 95% CI
12 34.50 4.00 1.15 (31.96, 37.04)
Which is the correct interpretation of the 95% confidence interval? We are 95% confident that the:
A) population proportion is between 31.96 to 37.04 hours/week.
B) sample proportion is between 31.96 to 37.04 hours/week.
C) population mean is between 31.96 to 37.04 hours/week.
D) sample mean is between 31.96 to 37.04 hours/week. - correct answer C) population mean is between 31.96 and 37.04 hours/week
A sample of 10 banks was obtained where both the overdraft fee ($) and the stop payment on a draft fee ($) were obtained for each bank when considering their basic checking option. The goal is to determine, by how much more, is the overdraft fee when compared to the stop payment on a draft fee, on the average.
The correct population parameter and inferential procedure in this instance are: ________
A) difference in the two population means: confidence interval
B) difference in the two population means: hypothesis test
C) population mean difference: confidence interval
D) population mean difference: hypothesis test
E) difference in the two population proportions: confidence interval - correct answer C) population mean difference: confidence interval
A national survey asked: "Have you cut back on eating out: ("yes" or "no")? The research question is: ls there a difference in the two population proportions of "yes's" when comparing (people who have jobs) to (people who do not have jobs).
The correct population of parameter and inferential procedure in this instance are:
A) population mean difference: hypothesis test
B) difference in the two population proportions: confidence interval
C) difference in the two population proportions: hypothesis test
D) difference in the two population means: confidence interval
E) difference in the two population means: hypothesis test - correct answer C) difference in the two population proportions: hypothesis test
Do wearing wetsuits allow swimmers to swim faster. Twelve competitive swimmers were asked to swim a 1500 meter trial twice at maximum speed: once when wearing a wetsuit and then again when wearing a regular bathing suit. The order of the trials were randomized such that 6 swimmers used the wet suit first while the other 6 swimmers used the regular bathing suit first. The maximum swimming velocity was recorded in meters/second. Does the data suggest that the population mean maximum speed is faster when wearing the wet suit?
N Mean StDev SE Mean
Yes 12 1.5067 0.1363 0.0393
No 12 1.4292 0.1411 0.0407
Difference 12 0.0775 0.0218 0.0062
95% lower bound for mean difference: 0.06620
T-Test of mean difference = 0 (vs > 0): T-Value = 12.32 P-Value = 0.000
Which is untrue?
A) d= .0775 meters/second
B) the two samples are dependent
C) were successful in getting rid of unwanted variation
D) a cause and effect statement can be included
E) the carry-over effect" is a possible problem - correct answer E) the carry over effect is a possible problem
Do people who fear going to the dentist make fewer visits to the dentist. A sample of 200 people who fear going to the dentist and a sample of 200 people who don't fear going to the dentist was obtained. Each person indicated the number of times that they have been to the dentist over the past three years. The goal is to determine if on the average, people who fear the dentist make fewer visits to the dentist.
The correct population parameter and inferential procedure in this instance are:
A) difference in the two population proportions: confidence interval
B) difference in the two population means: hypothesis test
C) difference in the two population means: confidence interval
D) population mean difference: hypothesis test
E) population mean difference: confidence interval - correct answer B) difference in the two population means: hypothesis test
At a given time: you have a choice of two flights between Chicago and New York. You know how many minutes each flight was late for a random sample of 15 days over the past year. Your goal is to determine if there is a difference in the mean number of minutes that a flight is late when comparing the the two flights. When considering the design for this study, what unwanted variation are you trying to get rid of? The variation from:
A) day to day
B) late time to late time
C) flight to flight
D) person to person - correct answer A) day to day
It is believed that a new instructional method will more effectively improve the reading ability of elementary school children. In order to test this conjecture, 16 children were divided at random into two groups. One group was instructed by the new method while the other group was instructed by the standard method. After four weeks, each student was given a reading test worth 50 pts.
Consider this 95% confidence interval.
Difference = mu (New ) - mu (Standard)
95% CI for difference: (4.70, 9.50)
Whch conclusion can be made with the confidence interval? At 95% confidence, we can claim that:
A) there is no difference in the two population means when comparing the new method to [Show Less]