AP Statistics Two Variable Data Review

The campus bookstore at a local university is interested in finding out whether the textbook preference and the class level (freshman, sophomore, junior, senior) of the student are associated. A random sample of 100 students is obtained, and each student in the sample is asked which textbook he or she prefers: new books, used books, or digital books. The students are also asked whether their class level is freshman, sophomore, junior, or senior. Which of the following is the appropriate test for the investigation?

A sample of 99 distances has a mean of 22 feet and a median of 22.5 feet. Unfortunately, it has just been discovered that the minimum value in the distribution, which was erroneously recorded as 15 actually has a value of 10. If we make this correction to the data, then

• The median decreases, but the mean remains the same

• The median remains the same, but the mean is decreased

• The median increases, but the mean decreases

• The median stays the same, but the mean increases

Jana, a high school principal, hosted a movie event at her school. Jana's assistant kept track of the number of students in each grade who attended the event. The distribution shown in the table represents the number of students in each grade that were present. Jana knows that the grade levels are equally distributed across the school of 1,200 students. She would like to use a chi-square test to see if the proportion of individuals in each class at the movie are also equally distributed. How many seniors would be expected at the event?

• 61.3

• 59.5

• 56.4

• 57.9

An agricultural economist says that the correlation between corn prices and soybean prices is r = 0.7. This means that...

• When corn prices are above average, soybean prices tend to stay the same

• When corn prices are below average, soybean prices tend to be above average

• When corn prices are above average, soybean prices tend to be below average

• When corn prices are above average, soybean prices also tend to be above average

Bivariate data is the study of how many variables?

• 3

• 1

• 2

• 0

___ data for two variables.

• trivariate

• bivariate

• positive

• negative

I have a confidence interval that is (22, 26). Assuming the standard deviation is 3 and the sample size is 13, what is the confidence level?

What is the branch of mathematics dealing with the collection, organization, analysis, interpretation and presentation of data?

• Algebra

• Geometry

• Probability

• Statistics

If the point with the red x is removed from the scatterplot, what will happen to the slope of the LSRL and the correlation coefficient?

• slope increases, r increases

• slope decreases, r increases

• slope increases, r decreases

• slope decreases, r decreases

• slope is unchanged, r increases

What is the value of the correlation coefficient?

• 0.891

• -0.891

• 0.875

• 0.943

• -0.943