# Web Activities

Click on the following links. Please note these will open in a new window.

## Activity 1:

Identifying hypotheses; t versus z distributions

Your book discussed null and alternative hypotheses. In this activity, you will generate null and alternative hypotheses.

Let’s say you are from the year 3017, and you have a sample of children born since 2017 and want to compare their average age based on their name to the population mean of their name identified by this website. (e.g., compare persons named Sophia to a prior sample of persons named Sophia).

Scientist A is unsure if the new cohort of Sophias will be older or younger than the population mean.
Scientist B thinks the new cohort of Sophias will be older.

1. Generate a null hypothesis for Scientists A and B.
2. Generate an alternative hypothesis for Scientists A and B.
3. Think about how the z distribution compares to the t distribution. What could you do to make your sample be more similar to a z distribution?

Activity 2:

Assumptions of a t test

Remind yourself what the two assumptions of a t test are.

Let’s say you are from the year 3017, and you have a sample of children born since 2017 and want to compare their average age based on their name to the population mean of their name identified by this website. (e.g., compare persons named Sophia to a prior sample of persons named Sophia).

Scroll down to Youngest Male names.

1. Identify at least three names that you think would violate the assumption of normality. Use what you know about the normal curve (that the mean, median, and mode are the same for a normal distribution, and the distribution is symmetrical in a normal distribution) to determine if the distribution is normal.
2. Identify at least three names that you think would meet the assumption of normality.

Scroll down to Youngest Female names.

1. Identify the name that most differs from normality.
2. What are three other names with non-normal (skewed) distributions?
3. What are three other names with normal distributions?

Activity 3:

(One sample) t test versus z test

Your book discusses the difference between a (one sample) t test and a z test. In this activity, you will apply this knowledge.

Scroll down to the second paragraph and read it in its entirety.

1. Does the web page provide enough information for a z test to compare children now to a previous population sample?
2. What is missing? Think about the equation for a z test and t test to answer this question.
3. How would you obtain this information? Would you have to go back to the raw data?