Answer: a. 69.72 ± 1.37
Step-by-step explanation:
We want to determine a 90% confidence interval for the mean height (in inches) of adult men in the United States.
Number of sample, n = 25
Mean, u = 69.72 inches
Standard deviation, s = 4.15
For a confidence level of 90%, the corresponding z value is 1.645. This is determined from the normal distribution table.
We will apply the formula
Confidence interval
= mean ± z × standard deviation/√n
It becomes
69.72 ± 1.645 × 4.15/√25
= 69.72 ± 1.645 × 0.83
= 69.72 ± 1.37
The lower end of the confidence interval is 69.72 - 1.37 = 68.35
The upper end of the confidence interval is 69.72 + 1.37 = 71.09
Mean= is the summation of the maximum temperatures ÷ the numbers of times the temperatures where recorded
standard deviation= is a number used to tell how measurements for a group are spread out from the average (mean), or expected value.
A low standard deviation means that most of the numbers are very close to the average.
A high standard deviation means that the numbers are spread out.
Variance= is a way to measure how far a set of numbers is spread out.
A variance of zero indicates that all of the data values are identical. All non-zero variances are positive.
A small variance indicates that the data points tend to be very close to the mean, and to each other.
A high variance indicates that the data points are very spread out from the mean, and from one another.
It is D if u did the math right
Well, if we divide 3.22 by 14 we get 0.23
0.23 +0.15 is 0.38
the answer would be $0.38
