Question

Group	Sample Mean	Std. Err.	DF	L. Limit	U. Limit
Infant	62.556325	1.5340462	331	59.538616	65.574035

WHO region	n	Mean	Variance	Std. dev.	Std. err.	Median	Range	Min	Max	Q1	Q3
Africa	336	104.16012	2217.9031	47.094618	2.5692221	92.3	296.4	30	326.4	70.65	128.7

Test if the African average infant mortality rate is different from 62.56 using the population standard deviation 27.91 and normal distribution for α=0.05.

Answer 1

we have population standard deviation ,

These values are provided in the data table given above.

We have to use the z distribution because the population standard deviation is known.

we have to test whether the Africa average infant mortality rate is different from 62.56 or not

So, null hypothesis will be

and alternate hypothesis will be

This is a two tailed hypothesis testing

Calculation for the test statistic

z statistic =

setting the given values, we get

z statistic =

Using the z distribution table for the z value of 1.49 (two tailed hypothesis), we get

p value = 0.1362

We failed to reject the null hypothesis because the p value is greater than 0.05 level of significance, which makes the p value insignificcant at 0.05 level.

Thus, we can conclude that we have insufficient evidence to support the claim that the African average infant mortality rate is different from 62.56.