Chapter 9. An interesting study by a toy company found that the mean age in months when toddlers first start to walk varies in each generation. However, the variance of that age remains constant of around 1.25 months. A survey of 35 toddlers from the current generation was done to test if the mean age for starting to walk is at least 13 months. The sample mean was 12.75 months with a sample standard deviation of 0.4 months. Do the data support the claim at the 2% level? Round decimals to 2 places, unless asked otherwise.

HINT: Remember that since we know the population variance, we should use that to perform the Z-test.

1. The null hypothesis for this question is mu >= 13. Write True/False:
2. What is the alpha value that we are considering to evaluate this problem?
3. What is the absolute value of the test-statistic?
4. What is the absolute critical value?
5. What is your final decision? (write "reject Ho" or "fail to reject Ho" in the blank):