How much does a sleeping bag cost? Let's say you want a sleeping bag that should keep you warm in temperatures from 20°F to 45°F. A random sample of prices ($) for sleeping bags in this temperature range is given below. Assume that the population of x values has an approximately normal distribution. 115 95 65 70 45 45 30 23 100 110 105 95 105 60 110 120 95 90 60 70 (a) Use a calculator with mean and sample standard deviation keys to find the sample mean price x and sample standard deviation s. (Round your answers to two decimal places.) x = $ s = $ (b) Using the given data as representative of the population of prices of all summer sleeping bags, find a 90% confidence interval for the mean price μ of all summer sleeping bags. (Round your answers to two decimal places.) lower limit $ upper limit $
How much does a sleeping bag cost? Let's say you want a sleeping bag that should keep you warm in temperatures from 20°F to 45°F. A random sample of prices ($) for sleeping bags in this temperature
| 115 | 95 | 65 | 70 | 45 | 45 | 30 | 23 | 100 | 110 |
| 105 | 95 | 105 | 60 | 110 | 120 | 95 | 90 | 60 | 70 |
| x = | $ |
| s = | $ |
(b) Using the given data as representative of the population of prices of all summer sleeping bags, find a 90% confidence interval for the mean price μ of all summer sleeping bags. (Round your answers to two decimal places.)
| lower limit | $ |
| upper limit | $ |
Note:
Thank you for the question. We have used an fx-82MS calculator to solve Part (a) for you.
(a)
Switch on the calculator.
Go to Mode > 2 (for SD)
Type 115 > Press on the button M+.
Type 95 > Press on the button M+.
Type 65 > Press on the button M+.
Proceed in this manner, till the last or 20th observation, 70 is stored in memory.
Press SHIFT > 2 (S-VAR should be written on top of 2, in the same color as the word SHIFT is written); press 1 (It represents x̄).
The mean is obtained as, x̄ = $80.40.
Press SHIFT > 2; press 2 (It represents sx, the sample standard deviation).
The sample standard deviation is obtained as, s = $29.44 (correct to 2 decimal places).
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