Q1
A company wants to determine a confidence interval for the average CPU time of its teleprocessing transactions. A sample of 70 random transactions in milliseconds is given below. Assume that the transaction times follow a normal distribution with a standard deviation of 600 milliseconds. Use Excel to determine a 98% confidence interval for the average CPU time in milliseconds. Round your answers to the nearest integer and use ascending order.
Time
6690
6160
5140
7210
5570
7320
5190
5770
8390
6730
6820
5340
6690
5560
6680
7270
5670
6650
6180
5570
5410
6160
6600
6910
6400
4960
5660
6360
5760
6270
6810
5860
5700
6730
4850
6160
6490
6790
6680
6160
5500
5490
5240
7020
5930
6280
5980
6380
5140
6270
6200
5770
5480
6090
6060
6380
4910
4170
6630
5990
4720
6510
5860
6610
5370
6510
5800
5660
5760
6110
Q2
In a random sample of 350 attendees of a minor league baseball game, 184 said that they bought food from the concession stand. Create a 95% confidence interval for the proportion of fans who bought food from the concession stand. Use Excel to create the confidence interval, rounding to four decimal places.
Q3
The monthly incomes from a random sample of 20 workers in a factory is given below in dollars. Assume the population has a normal distribution and has standard deviation $518. Compute a 98% confidence interval for the mean of the population. Round your answers to the nearest dollar and use ascending order.
Monthly Income
11621
12367
12030
12135
12561
11453
12313
11561
12424
12346
11591
12032
11562
12224
12850
11802
12360
12519
11960
12337
Q4
A sample of 22 test-tubes tested for number of times they can be heated on a Bunsen burner before they crack is given below. Assume the counts are normally distributed. Use Excel to construct a 99% confidence interval for μ. Round your answers to two decimal places and use increasing order.
Number of times test-tubes can be heated
1189
886
921
1021
1074
1233
1697
1293
747
1233
1158
1536
1961
922
1546
1157
1814
1334
1434
1079
1830
975
Q5
In a survey of 603 adults, 98 said that they regularly lie to people conducting surveys. Create a 99% confidence interval for the proportion of adults who regularly lie to people conducting surveys. Use Excel to create the confidence interval, rounding to four decimal places.
Q6
Weights, in pounds, of ten-year-old girls are collected from a neighborhood. A sample of 26 is given below. Assuming normality, use Excel to find the 98% confidence interval for the population mean weight μ. Round your answers to three decimal places and use increasing order.
Weight
66.4
86.3
71.3
52.8
68.0
85.0
66.2
79.2
93.5
84.5
71.1
74.5
65.0
58.5
59.8
80.2
69.2
92.9
78.9
59.4
63.6
66.5
60.7
80.1
60.4
74.5
Q7
In a survey of 1,000 adults in a country, 722 said that they had eaten fast food at least once in the past month. Create a 95% confidence interval for the population proportion of adults who ate fast food at least once in the past month. Use Excel to create the confidence interval, rounding to four decimal places.
Q8
A city is holding a referendum on increasing property taxes to pay for a new high school. In a survey of 458 likely voters, 254 said that they would vote “yes” on the referendum. Create a 95% confidence interval for the proportion of likely voters who will vote “yes” on the referendum. Use Excel to create the confidence interval, rounding to four decimal places.
Q9
The yearly incomes, in thousands, for 24 random married couples living in a city are given below. Assume the yearly incomes are approximately normally distributed. Use Excel to find the 95% confidence interval for the true mean, in thousands. Round your answers to three decimal places and use increasing order.
Yearly Income
59.015
58.962
58.935
58.989
58.997
58.970
59.000
59.014
59.001
59.003
58.992
58.926
59.032
58.958
59.093
58.955
59.003
58.952
59.057
59.056
59.074
59.128
59.001
59.007
Q10
In a city, 22 coffee shops are randomly selected, and the temperature of the coffee sold at each shop is noted. Use Excel to find the 90% confidence interval for the population mean temperature. Assume the temperatures are approximately normally distributed. Round your answers to two decimal places and use increasing order.
Temperature
151
158
163
155
155
144
140
148
145
146
158
143
152
167
163
171
147
177
170
168
176
164
Q11
Suppose the weights of tight ends in a football league are normally distributed such that σ2=1,369. A sample of 49 tight ends was randomly selected, and the weights are given below. Use Excel to calculate the 95% confidence interval for the mean weight of all tight ends in this league. Round your answers to two decimal places and use ascending order.
Weight
300
294
155
270
218
242
150
364
298
167
297
299
221
266
261
301
269
267
219
165
198
359
240
263
160
171
169
259
196
197
268
271
200
295
258
199
260
303
264
241
220
265
262
343
321
302
364
296
170
Q12
The following data represent a sample of the assets (in millions of dollars) of 28 credit unions in a state. Assume that the population in this state is normally distributed with σ=3.5 million dollars. Use Excel to find the 99% confidence interval of the mean assets in millions of dollars. Round your answers to three decimal places and use ascending order.
Assets
12.23
2.89
13.19
73.25
11.59
8.74
7.92
40.22
5.01
2.27
16.56
1.24
9.16
1.91
6.69
3.17
4.78
2.42
1.47
12.77
4.39
2.17
1.42
14.64
1.06
18.13
16.85
21.58
Q13
Gary is studying the prevalence of regional dialects. He surveyed 351 people in a region and asked what words they used for certain things. 292 of the respondents referred to soft drinks as “pop,” as opposed to “soda” or “cola.” Create a 90% confidence interval for the proportion of people in this region who refer to soft drinks as “pop.” Use Excel to create the confidence interval, rounding to four decimal places.
Q14
A business magazine conducted a survey of 751 employees who had been at their current employer for 5 or more years. Of these employees, 295 responded that they were bored in their current position. Create a 99% confidence interval for the proportion of employees who have been with their current employer for 5 or more years and reported being bored in their current position. Use Excel to create the confidence interval, rounding to four decimal places.
Solution
Q1
A company wants to determine a confidence interval for the average CPU time of its teleprocessing transactions. A sample of 70 random transactions in milliseconds is given below. Assume that the transaction times follow a normal distribution with a standard deviation of 600 milliseconds. Use Excel to determine a 98% confidence interval for the average CPU time in milliseconds. Round your answers to the nearest integer and use ascending order.
Time
6690
6160
5140
7210
5570
7320
5190
5770
8390
6730
6820
5340
6690
5560
6680
7270
5670
6650
6180
5570
5410
6160
6600
6910
6400
4960
5660
6360
5760
6270
6810
5860
5700
6730
4850
6160
6490
6790
6680
6160
5500
5490
5240
7020
5930
6280
5980
6380
5140
6270
6200
5770
5480
6090
6060
6380
4910
4170
6630
5990
4720
6510
5860
6610
5370
6510
5800
5660
5760
6110
Ans: (5,906, 6,240).
Q2
In a random sample of 350 attendees of a minor league baseball game, 184 said that they bought food from the concession stand. Create a 95% confidence interval for the proportion of fans who bought food from the concession stand. Use Excel to create the confidence interval, rounding to four decimal places.
Ans: (0.4734, 0.5780)…………..please follow the link below to purchase all the solutions at $10
