Question

Question 3. It is posited that babies born at different times of the year may develop the ability to crawl at different ages. Thirty two babies born in January crawled at an average age of 29.75 weeks, with a standard deviation of 7 weeks. Another 32 babies born in August crawled at an average of 33.5 weeks with a standard deviation of 7 weeks. Test whether the posited claim is true. Use α=0.05. Use RStudio or R on Jupyter in order to solve this problem. Provide all your work with your solutions. How valid is the test you conducted? In order to answer this question, • List all assumptions required. • For each assumption, indicate whether it holds and why it does or does not. • Can you provide graphical displays in order to assess a particular assumption? • What would you need in order to produce such graphs?

Answer 1

Assumptions:
1. The sample observations are independent
2. The samples are taken from normal distribution
3. The variable must be in ordinal or continuous scale
4. The population SD is not known

H0: The babies born at different times of the year may not develop the ability to crawl at different ages

H1: The babies born at different times of the year may develop the ability to crawl at different ages

Let the los be alpha = 5%

R-code:

Here test statistic t value is not in t critical values so we reject H0

Thus we conclude that the babies born at different times of the year may not develop the ability to crawl at different ages

Graph: