Question

The weights of newborn children in the United States vary according to the normal distribution with a mean of 7.5 pounds and a standard deviation of 1.25 pounds. An article in The Wall Street Journal claims that the average birth weight is decreasing over time. A local hospital wanted to see if the claim was true and randomly sampled 22 baby's weights and found an average weight of 7.3 pounds. Test the claim using a 10

1) Yes, there is enough evidence to support the claim
2) No, there is not enough evidence to support the claim

Answer 1

To test the claim, we can use a hypothesis test with a significance level of 0.10.

Step-by-step explanation:

To test the claim that the average birth weight is decreasing, we can use a hypothesis test. The null hypothesis is that the mean birth weight is equal to 7.5 pounds, and the alternative hypothesis is that the mean birth weight is less than 7.5 pounds. Using a significance level of 0.10, we can calculate the test statistic and compare it to the critical value from the student's t-distribution table. In this case, the test statistic is calculated as (sample mean - population mean)/(standard deviation/sqrt(sample size)). If the test statistic is less than the critical value, we reject the null hypothesis and conclude that there is enough evidence to support the claim that the average birth weight is decreasing. If the test statistic is greater than the critical value, we fail to reject the null hypothesis and conclude that there is not enough evidence to support the claim.