Question
A sample of 40 songs from a student’s iTunes playlist showed a mean length of 3.542...
A sample of 40 songs from a student’s iTunes playlist showed a mean length of 3.542 minutes with a standard deviation of 0.311 minute. Construct a 95% confidence interval for the population standard deviation. (Round your answers to 4 decimal places.)
Homework Answers
Answer #1
Solution :
Given that,
s = 0.311
s2 = 0.096721
2L
=
2
/2,df
= 58.120
2R
=
21 -
/2,df = 23.654
The 95% confidence interval for 
is,
(n
- 1)s2 /
2/2
<
<
(n - 1)s2 /
21 -
/2
39
* 0.096721 / 58.120 <
<
39 * 0.096721 / 23.654
0.2548 <
< 0.3993
(0.2548 , 0.3993)
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