Question

"A hypothesis regarding the weight of newborn infants at a community hospital is that the mean is 6.6 pounds. A sample of seven infants is randomly selected and their weights at birth are recorded as 9.0, 7.3, 6.0, 8.8, 6.8, 8.4, and 6.6 pounds. The null hypothesis is ______."

Answer 1

the null hypothesis is that the average is 7.55 in the sample presented

Explanation:

We are told that there is a hypothesis that the average in a hospital is 6.6 pounds.

A random sampling of 7 babies is made: 9.0, 7.3, 6.0, 8.8, 6.8, 8.4 and 6.6 pounds.

Let's calculate the mean:

m = (9.0 + 7.3 + 6.0 + 8.8 + 6.8 + 8.4 + 6.6) / 7

m = 7.55 pounds.

This means that the sample taken from this hospital contradicts the hypothesis proposed at the beginning, since it is a value that exceeds the aforementioned average.

The hypothesis would be valid if it had been mentioned that the mean is 6.6 + - 1.

That is, the maximum value would be 7.6 pounds, therefore it would be valid there.

But this is not the case, therefore the null hypothesis is that the average is 7.55 in the sample presented