Help please, my brains is empty :o(
1 answer:
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Answer:
0 < 0.05, which means that we reject the null hypothesis, meaning that the air pressure of the balls is different of the target value of 7.9.
Step-by-step explanation:
The air pressure of a particular ball has a target value of 7.9 PSI.
This means that the null hypothesis is:
The alternate hypothesis is:
The test statistic is:
In which X is the sample mean, is the value tested at the null hypothesis,
is the standard deviation and n is the size of the sample.
The hypothesis tested means that
Suppose the basketballs have a normal distribution with a standard deviation of 0.20 PSI.
This means that
When a shipment of basketballs arrive, the consumer takes a sample of 21 from the shipment and measures their PSI to see if it meets the target value, and finds the mean to be 7.3 PSI.
This means that
The test statistic is:
pvalue:
We are testing that the mean pressure is different than the target value of 7.9, and since the test statistic is negative, the pvalue is 2 multiplied by the pvalue of z = -13.74, which we find looking at the z-table.
has a pvalue of 0.
2*0 = 0
0 < 0.05, which means that we reject the null hypothesis, meaning that the air pressure of the balls is different of the target value of 7.9.