AP Statistics Chapter 11

The bigger the chi square statistic, the ________ the p value.

• bigger

• smaller

What is the
χ² _calculated value for the following situation.

• 6.65

• 6.66

• 4.5

• 6.3

Using a computer program, the chi-square test statistic for the commuter data is c2 = 5.37 with P-value < 0.01. If we use a = 0.05, what conclusion is appropriate?

• a)Don’t reject H₀; the results are significant.

• b)Don’t reject H₀; the results are not significant.

• c)Reject H_0; the results are significant.

• d)Reject H₀; the results are not significant.

A chi-square test is used to test whether a 0 to 9 spinner is "fair" (that is, the outcomes are all equally likely).  The spinner is spun 100 times, and the results are recorded.  The degrees of freedom for the test will be

• 8

• 9

• 10

• 99

A chi-square test is used to test whether a 0 to 9 spinner is "fair" (that is, the outcomes are all equally likely).  The spinner is spun 100 times, and the results are recorded.  The expected counts for spinning a 5 will be

• 5

• 10

• 11.1

• 20

Popular wisdom is that eating presweetened cereal tends to increase the number of cavities in children. A sample of children was entered into a study and followed for several years. Each child was classified as a sweetened-cereal lover or a unsweetened cereal lover. At the end of the study, the amount of tooth damage was measured. The summary data is given. Assuming the necessary conditions for inference are met, which of the following is an approximate 95% confidence interval for the difference in the mean tooth damage?

You are constructing a 90% confidence interval for the difference of means from simple random samples from two independent populations. The sample sizes are n₁= 6 and n₂ =14. You draw dot plots of the samples to check the normality condition for two-sample t-procedures. Which of the following descriptions of those dot plots would suggest that it is safe to use t-procedures?

• I only

• II only

• I and II

• I, II, and III

• none of the above

An appropriate 95% confidence interval for μ has been calculated as ( − 0.73, 1.92) based on n = 15 observations from a population with a Normal distribution. If we wish to use this confidence interval to test the hypothesis Ho: μ = 0 against Ha: μ ≠0, which of the following is a legitimate conclusion?

• Reject Ho at the

  α = 0.05 level of significance.

• Fail to reject Ho at the α = 0.05 level of significance.

• Reject Ho at the

  α = 0.10 level of significance.

• Fail to Reject Ho at the α = 0.10 level of significance.

• We cannot perform the required test since we do not know the value of the test statistic.

A coach uses a new technique in training middle distance runners. The times for 9 different athletes to run 800 meters before and after this training are shown. Construct a 99% confidence interval for the mean difference

• (-6.42, 8.87)

• (-0.76, 3.20)

• (-0.85, 3.29))

• (-0.54, 2.98)

• (-0.82, 3.27)

Five students took a math test before and after tutoring. Their scores were as follows. Do the data suggest that there is a difference in the math scores? Perform a paired t-test at the 5% significance level.

• No, the data do not provide sufficient evidence to conclude that the tutoring has an effect on the math scores.

• Yes, the data do provide sufficient evidence to conclude that the tutoring has an effect on the math scores.