PROBLEM # 14 The manager of gas station would like to estimate the mean number of litres (L)
of gasoline sold to his customers. Assume the number of litres sold follows the normal
distribution with a standard deviation of 34 L. From his records, he selects a random sample of
26 sales and finds the mean number of litres sold is 80. Use these tables to determine the z-
value(s)
a. What is the point estimate of the population mean?
The point estimate of the population mean is litres. (Round it to the nearest whole number.)
b. Explain what distribution you will use and why.
(Click to select) z distribution because the population standard deviation is known. t
distribution because the population standard deviation is unknown. z distribution because the
sample mean is known. t distribution because the sample mean is unknown. z distribution
because the the confidence interval is for a population proportion. t distribution because the the
confidence interval is for a population proportion.
c. For a 92% confidence interval, what is the value z or t (depending on your answer in b.)?
The value of z or t is .
d. Develop a 92% confidence interval for the population mean.
The 92% confidence interval for the population mean is between and . (Round each to 3
decimal places.)
e. Interpret the meaning of part (d).
If 100 such intervals were determined, the (Click to select) population mean sample variance
sample statistic sample mean population variance would appear in about of those intervals..
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PROBLEM # 14 The manager of gas station would like to estimate the m.pdf
1. PROBLEM # 14 The manager of gas station would like to estimate the mean number of litres (L)
of gasoline sold to his customers. Assume the number of litres sold follows the normal
distribution with a standard deviation of 34 L. From his records, he selects a random sample of
26 sales and finds the mean number of litres sold is 80. Use these tables to determine the z-
value(s)
a. What is the point estimate of the population mean?
The point estimate of the population mean is litres. (Round it to the nearest whole number.)
b. Explain what distribution you will use and why.
(Click to select) z distribution because the population standard deviation is known. t
distribution because the population standard deviation is unknown. z distribution because the
sample mean is known. t distribution because the sample mean is unknown. z distribution
because the the confidence interval is for a population proportion. t distribution because the the
confidence interval is for a population proportion.
c. For a 92% confidence interval, what is the value z or t (depending on your answer in b.)?
The value of z or t is .
d. Develop a 92% confidence interval for the population mean.
The 92% confidence interval for the population mean is between and . (Round each to 3
decimal places.)
e. Interpret the meaning of part (d).
If 100 such intervals were determined, the (Click to select) population mean sample variance
sample statistic sample mean population variance would appear in about of those intervals.
