The manager of The Cheesecake Factory in Boston reports that on six randomly selected weekdays, the number of customers served was 175, 125, 180, 220, 240, and 245. She believes that the number of customers served on weekdays follows a normal distribution. Construct the 99% confidence interval for the average number of customers served on weekdays. Use Table 2. (Round intermediate calculations to 4 decimal places, "sample mean" and "sample standard deviation" to 2 decimal places. Round "t" value to 3 decimal places and final answers to 2 decimal places.) Confidence interval to
First enter Data into EXCEL
We have to find the sample mean.
Excel command is =AVERAGE(Select data)
sample mean = = 197.5
Now we have to find sample standard deviation.
Excel command is =STDEV(Select data)
standard deviation = s = 46.13
n = 6
= 197.5
s = 46.13
99 % confidence interval
Formula
tc =4.032 ( using t-table )
99 % confidence interval is
The manager of The Cheesecake Factory in Boston reports that on six randomly selected weekdays, the...
The manager of The Eastside Brewery in Chicago reports that on six randomly selected weekdays, the number of customers served was as follows: 120 130 1100 205 185 220 She believes that the number of customers served on weekdays follows a normal distribution. a. Construct the 95% confidence interval for the average number of customers served on weekdays. (Round answers to 2 decimal places.) Confidence interval to b. How can the margin of error reported in part a be reduced?...
In a poll of 125 randomly selected U.S. adults, 67 said they favored a new proposition. Based on this poll, compute a 99% confidence interval for the proportion of all U.S. adults in favor of the proposition (at the time of the poll). Then complete the table below. Carry your intermediate computations to at least three decimal places. Round your answers to two decimal places. What is the lower limit of the 99% confidence interval? What is the upper limit...
A survey of 25 randomly selected customers found the ages shown (in years). The mean is 32.00 years and the standard deviation is 9.99 3 years. a Construct a 99% confidence interval for the mean age of all customers, assuming that the assumptions and conditions or the con interval have been met b) How large is the margin of error? c) How would the confidence interval change i you had assumed that the standard deviation was known to be 10.0...
A survey of 41 randomly selected "iPhone" owners showed that the purchase price has a mean of $414 with a sample standard deviation of $180. a. Compute the standard error of the sample mean. (Round the final answer to the nearest whole number.) Standard error b. Compute the 80% confidence interval for the mean. (Round the final answers to 2 decimal places.) The confidence interval is between $ and $ . c. How large a sample is needed to estimate...
A small hair salon in Denver, Colorado, averages about 30 customers on weekdays with a standard deviation of 6. It is safe to assume that the underlying distribution is normal. In an attempt to increase the number of weekday customers, the manager offers a $2 discount on 5 consecutive weekdays. She reports that her strategy has worked since the sample mean of customers during this 5 weekday period jumps to 35. Use Table 1. a. What is the probability to...
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A small hair salon in Denver, Colorado, averages about 62 customers on weekdays with a standard deviation of 16. It is safe to assume that the underlying distribution is normal. In an attempt to increase the number of weekday customers, the manager offers a $3 discount on 9 consecutive weekdays. She reports that her strategy has worked since the sample mean of customers during this 9 weekday period jumps to 74. Use Table 1. a. What is the probability to...
Refer to the data set of 20 randomly selected presidents given below. Treat the data as a sample and find the proportion of presidents who were taller than their opponents. Use that result to construct a 95% confidence interval estimate of the population percentage. Based on the result, does it appear that greater height is an advantage for presidential candidates? Why or why not? Construct a 95% confidence interval estimate of the percentage of presidents who were taller than their...
9 The state test scores for 12 randomly selected high school seniors are shown on the right Complete parts (a) through (c) below Assume the population is normally distributed. 1422 691 722 622 1224 723 742 1443 987 835 550 943 (a) Find the sample mean x=(Round to one decimal place as needed.) (b) Find the sample standard deviation $=(Round to one decimal place as needed.) (c) Construct a 99% confidence interval for the population mean A 99% confidence interval...