1. A researcher (T. J.) wants to know if the mean number of children per family is still what 1997 almanac says it is: 2.53. The researcher locates 10 random families and records the number of children. The data is given below. Perform a t-test to test the hypothesis that the average family size has not changed.

2. The Little Red Hen Elementary school wants to implement a new lunch program designed to curb obesity. You are asked to test whether the program works. The weights of 10 random students were gathered in 2001 (before the program). Another 10 random students were checked in 2003 (after the program). The data is given in the chart below. Run a t-test to check if the program works.

3. In T. J.'s stat class, data was collected relating how many hours a student slept with their quiz score the following morning. Draw a scatterplot of this data. What do you conclude from it?

Draw a histogram of the quiz scores. Draw another histogram of the hours of sleep. What do you conclude from these?

4. Students is T.J.'s stat class will pass their statistics test if they get a score of 70 or more (out of 100). Statistics test scores are normally distributed with a mean of 78.55 and a standard deviation of 7.8. What percentage of students can expect to get passing grades? (Draw a shaded normal plot.) If there are 104 students in the class, how many of them should expect to pass?

Here are the solutions.

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