Answer:
a) s=64.65
b)
c)
d)
Step-by-step explanation:
a) To calculate the sample standard deviation, first we have to calculate the sample mean.
Now, the standard deviation is:
b) The z-value for a 95% confidence interval is z=1.96.
The margin of error is
The lower and upper limit of the CI are:
The confidence interval is:
c) In this case, the z-value for a 82% CI is z=1.34.
The margin of error is
The lower and upper limit of the CI are:
The confidence interval is:
c) Now we have to construct a one sided 95% confidence interval, with only one bound (lower bound).
The z-value is z=1.645
The margin of error is
The lower limit of the CI is:
The confidence interval is: