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1 answer:
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Answer:
The Correct answer is last option i.e 4.
Therefore,
Step-by-step explanation:
Given:
StartFraction negative 2 (7 minus 15) over 4 EndFraction
Means
Minus sign will enter in it and ( - ) × ( - ) = ( + )
Therefore,
Answer:
1) Since we know the info from all the students that he teaches and we know the population deviation from past data we can use a z test to check the hypothesis
2)
3)
Since the p value is lower than the significance level of 0.01 we have enough evidence to reject the null hypothesis in favor of the alternative hypothesis
4) For this case since we reject the null hypothesis we have enough evidence ot conclude that the scores for this semester are above the historical value of 78 so then the claim stated by the teacher makes sense
Step-by-step explanation:
Part 1
Since we know the info from all the students that he teaches and we know the population deviation from past data we can use a z test to check the hypothesis
Part 2
represent the sample mean for the scores
represent the population standard deviation
n=120 represent the sample selected
significance level
System of hypothesis
He wants to test if the group for this current semester is above the average of the classes he has taught (mean 78), the system of hypothesis are:
Null hypothesis:
Alternative hypothesis:
Since we know the population deviation we can use the following statistic
(1)
Replacing the info given we got:
Part 3
We can calculate the p value for this test with this probability taking in count the alternative hypothesis:
Since the p value is lower than the significance level of 0.01 we have enough evidence to reject the null hypothesis in favor of the alternative hypothesis
Part 4
For this case since we reject the null hypothesis we have enough evidence ot conclude that the scores for this semester are above the historical value of 78 so then the claim stated by the teacher makes sense