Question

1. For a confidence level of 96%, find the critical value for a normally distributed variable. The sample mean is normally distributed if the population standard deviation is known. 2. You intend to estimate a population mean with a confidence interval. You believe the population to have a normal distribution. Your sample size is 7. Find the critical value that corresponds to a confidence level of 98%. (Report answer accurate to three decimal places with appropriate rounding.) ta/2 = ±± 3. You measure 27 textbooks' weights, and find they have a mean weight of 52 ounces. Assume the population standard deviation is 7.7 ounces. Based on this, construct a 95% confidence interval for the true population mean textbook weight. Give your answers as decimals, to two places < μμ < 4. You are interested in finding a 90% confidence interval for the average commute that non-residential students have to their college. The data below show the number of commute miles for 12 randomly selected non-residential college students. Round answers to 3 decimal places where possible. 18 26 22 12 9 23 8 14 5 7 15 22 a. To compute the confidence interval use a ? z t distribution. b. With 90% confidence the population mean commute for non-residential college students is between and miles. c. If many groups of 12 randomly selected non-residential college students are surveyed, then a different confidence interval would be produced from each group. About percent of these confidence intervals will contain the true population mean number of commute miles and about percent will not contain the true population mean number of commute miles.

          1. For a confidence level of 96%, find the critical value for a
normally distributed variable. The sample mean is normally
distributed if the population standard deviation is known.
2. You intend to estimate a population mean with a
confidence interval. You believe the population to have a normal
distribution. Your sample size is 7.
Find the critical value that corresponds to a confidence level of
98%.
(Report answer accurate to three decimal places with
appropriate rounding.)
ta/2 = ±±
3. You measure 27 textbooks' weights, and find they have a
mean weight of 52 ounces. Assume the population standard deviation
is 7.7 ounces. Based on this, construct a 95% confidence interval
for the true population mean textbook weight.
Give your answers as decimals, to two places
 < μμ < 
4. You are interested in finding a 90% confidence interval
for the average commute that non-residential students have to their
college. The data below show the number of commute miles for 12
randomly selected non-residential college students. Round answers
to 3 decimal places where possible.
18
26
22
12
9
23
8
14
5
7
15
22
a. To compute the confidence interval use
a ? z t  distribution.
b. With 90% confidence the population mean commute for
non-residential college students is between  and
  miles.
c. If many groups of 12 randomly selected non-residential
college students are surveyed, then a different confidence interval
would be produced from each group. About  percent of
these confidence intervals will contain the true population mean
number of commute miles and about  percent will not
contain the true population mean number of  commute
miles.

Added by Erin M.

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