Question

A confidence interval for a population mean has length 26.

a) Determine the margin of error.

b) If the sample mean is 58.9, obtain the confidence interval.
Confidence interval: ( , ).

Lindsey thinks a certain potato chip maker is putting fewer chips in their regular bags of chips. From a random sample of 23 bags of potato chips she calculated a P value of 0.029 for the sample.

(a) At a 5% level of significance, is there evidence that Lindsey is correct? (Type: Yes or No):

(b) At a 10% level of significance, is there evidence that she is correct? (Type: Yes or No):

(c) In a statistical test of hypotheses, we say that the data are statistically significant at level ?α if  

A. ?=0.05
B. ? is small.
C. the P - value is larger than ?
D. the P - value is less than ?.

Answer 1

A confidence interval for a population mean has length 26.

a) Determine the margin of error.

Margin of error = lenngth/2 = 26/2 = 13

Margin of error = 13

b) If the sample mean is 58.9, obtain the confidence interval.

Lower limit = 58.9 - 13

Upper limit = 58.9 + 13
Confidence interval: ( 45.9, 71.9)

Lindsey thinks a certain potato chip maker is putting fewer chips in their regular bags of chips. From a random sample of 23 bags of potato chips she calculated a P value of 0.029 for the sample.

(a) At a 5% level of significance, is there evidence that Lindsey is correct? (Type: Yes or No):

Ha: Claim :certain potato chip maker is putting fewer chips in their regular bags of chips

p value < 0.05 hence reject Ho

• Yes

(b) At a 10% level of significance, is there evidence that she is correct? (Type: Yes or No):

Ha: Claim :certain potato chip maker is putting fewer chips in their regular bags of chips

p value < 0.10 hence reject Ho

• Yes

(c) In a statistical test of hypotheses, we say that the data are statistically significant at level ? if  

D. the P - value is less than ?.