Chapter 8 - Hypothesis Testing: Z and t Tests
In testing for differences between the means of two related populations, the null hypothesis is:
H0 : ud = 0
A researcher is curious about the effect of sleep on students' test performances. He chooses 100 students and gives each student two exams. One is given after four hours' sleep and one after eight hours' sleep. The statistical test the researcher should use is the:
Paired t test
A statistics professor wanted to test whether the grades on a statistics test were the same for her morning class and her afternoon class. For this situation, the professor should use the:
Pooled-variance t test.
In testing a hypothesis about the difference between two proportions, the p-value is computed to be 0.034. The null hypothesis should be rejected if the chosen level of significance is 0.01. (true or false)
false
In testing a null hypothesis about the difference between two proportions, the Z test statistic is computed to be 2.04. The p-value is 0.0207. (true or false)
false
The sample size in each independent sample must be the same in order to test for differences between the means of two independent populations. (true or false)
false
The sample size in each independent sample must be the same in order to test for differences between the proportions of the two independent populations. (true or false)
false
You can use a pie chart to evaluate whether the assumption of normally distributed populations in the pooled-variance t test has been violated. (true or false)
false
The t test for the difference between the means of two independent populations assumes that the two:
populations are normally distributed
If the assumption of normally distributed populations in the pooled-variance t test has been violated, you should use an alternative procedure such as the nonparametric Wilcoxon rank sum test. (true or false)
true
In testing a hypothesis about the difference between two proportions, the p-value is computed 0.043. The null hypothesis should be rejected if the chosen level of 0.05. (true or false)
true
In testing a hypothesis about the difference between two proportions, the p-value is computed to be 0.043. The null hypothesis should be rejected if the chosen level of significance is 0.05. (true or false)
true
Repeated measurements from the same individuals are an example of data collected from two related populations. (true or false)
true
The pooled-variance t test assumes that the population variances in the two independent groups are equal. (true or false)
true
When you are sampling the same individuals and taking a measurement before treatment and after treatment, you should use the paired t test. (true or false)
true
