A researcher wants to know if there was a relationship between student age and desire to complete a college degree. To answer this question, the
... [Show More] researcher used a local community college as the sampling frame and then used stratified sampling to get a sample of students from 18 to 80 years old. Based on the information given, is there any potential bias in this study?
a Yes, because the sampling frame does not match the intended population of the question.
b Yes, because the sampling method will not give a representative sample.
c Yes, because a voluntary sample should have been used.
d No, there will likely be no bias in this study. - ANSWERSYes, because the sampling frame does not match the intended population of the question.
A researcher conducts an observational study and finds a correlation between managers' income and the number of college credits earned. The correlation coefficient was r=.85 with a regression equation of y=515x+12000. What can you say about the relationship between these variables?
a There is an association between these variables
b There is a causation between these variables.
c There is no relationship between these variables.
d There is not enough information to determine the relationship between the variables. - ANSWERSThere is an association between these variables
What technique is used to estimate the profit margin for a production level of 25 thousand units, if a line of best fit is created to estimate profit margin for production levels between 20 to 39 thousand units?
a Interpolation
b Linearization
c Extrapolation
d Internalization - ANSWERSInterpolation
What is the most appropriate definition of a scatterplot?
a A graph that uses dots to demonstrate relationships between two categorical variables.
b A graph where lines are shown to represent positive or negative trends.
c A graph where the explanatory and response variables are plotted as ordered pairs.
d A graph where a positive causation is always represented with dots forming a straight line. - ANSWERSA graph where the explanatory and response variables are plotted as ordered pairs.
What does a strong positive correlation between two variables suggest?
a The explanatory variable is increasing and the response variable is decreasing
b There is an association between the variables
c There is a causation between the variables
d Cannot determine - ANSWERSThere is an association between the variables
{{ Scatterplot of distance from city center vs. rent. The linear equation for this scatterplot is y equals negative one hundred five ten thousandths times x plus ten and three hundred eighty one thousandths. }}
Using the scatterplot Distance from City Center vs. Monthly Rent, how far can we expect an apartment to be from the city center if the monthly rent is $ 980 ? Round your answer to the nearest mile.
a Around 54 miles
b Around 55 miles
c Around 56 miles
d Around 57 miles - ANSWERSAround 55 miles
Which correlation coefficient suggests the weakest correlation?
a −0.9
b −0.3
c 0.1
d 1 - ANSWERS0.1
What does it mean for a result or relationship to be statistically significant?
a The relationship is not caused by mere chance.
b The relationship is caused by chance.
c Your hypothesis test has failed.
d Your significance level is not high enough. - ANSWERSThe relationship is not caused by mere chance.
What is the process used to create the equation for the line of best fit?
a Completing the square
b Least squares estimation
c Fitting the line to the curve
d Linear approximation - ANSWERSLeast squares estimation
A relationship between two or more variables is known as a(n) ________.
a Causation
b Association
c Cause and effect
d Correlation - ANSWERSAssociation
Using a line of best fit in slope-intercept form, y=mx+b , what must be true if there is a positive correlation?
a m must be >0 .
b b must be >0 .
c Both m and b must be >0 .
d Both m and b must have the same sign. - ANSWERSm must be >0.
Consider the following equation, y=−3.2x+2.8 . What is the y -intercept for this equation?
a −3.2
b 3.2
c 2.8
d −2.8 - ANSWERS2.8
When linear regression is used to show there is a linear association between two variables, we know the relationship is:
a A causation
b A correlation
c Neither A nor B
d Both A and B - ANSWERSA correlation
A restaurant owner wants to see if she can use low temperatures to boost soup sales at her restaurant. To study a possible relationship between temperature and soup sales, she collects data throughout the year on the temperature of a given day (ranging between 20 degrees F and 90 degrees F) and the amount of soup sold that day. She performs a linear regression and comes up with a least squares regression line of y=−1.64x+176.6 with r=−0.89 where x is the temperature (in degrees F) and y is the number of daily soup sales. How much soup should she expect to sell on a day that is 50 degrees F? Round to the nearest integer.
a 177 orders of soup
b 95 orders of soup
c 259 orders of soup
d 101 orders of soup - ANSWERS95 orders of soup
The line of best fit is also known as:
a The extrapolation line
b The regression line
c The interpolation line
d None of the above - ANSWERSThe regression line
If a trend appears in a large sample of data, the trend may not be replicated if the sample is broken up into smaller subsets. What is this effect known as?
a Foster's Theorem
b Bayes' Theorem
c Simpson's Paradox
d Consistency Construct - ANSWERSSimpson's Paradox
A variable not included in the study that is related to the measured variables in a study is called a ____________.
a Independent variable
b Confounding variable
c Dependent variable
d Lurking variable - ANSWERSLurking variable
Using the scatterplot below, what type of correlation is suggested? Scatterplot displaying data points distributed from lower left to upper right. Points are relatively close to one another.
a No correlation
b Weak negative positive
c Moderate positive
d Strong negative - ANSWERSModerate positive
What must be true about the dots on a scatterplot if there is no correlation?
a The dots are far away from the line of best fit.
b The dots form no recognizable linear pattern.
c The dots are evenly spaced around the graph.
d The dots form a non-linear pattern. - ANSWERSThe dots form no recognizable linear pattern.
What is (are) a potential problem(s) that can occur when attempting to use regression analysis?
a Extrapolation
b Lurking variables
c Inappropriate sampling
d A, B, and C - ANSWERSA, B, and C
A researcher conducts an experimental study and finds a correlation between salary and levels of experience. The correlation coefficient was r=.75 with a regression equation of y=515x+17500 . What can you say about the relationship between these variables?
a There is an association between these variables [Show Less]