A random sample of 16 pharmacy customers showered the waiting times below (in minutes) 17 18 16 20 20 12 19 19 15 27 14 23 15 25 18 20 Find the 90% confidence interval for y (but backward), assuming that the sample is from a normal population. (Round your standard deviation answer to 4 decimal places and t-value to 3 decimal places. Round answers to 3 decimal places) The 90% confidence interval ______ to _______.
A random sample of 16 pharmacy customers showered the waiting times below (in minutes)
17 18 16 20 20 12 19 19
15 27 14 23 15 25 18 20
Find the 90% confidence interval for y (but backward), assuming that the sample is from a normal population. (Round your standard deviation answer to 4 decimal places and t-value to 3 decimal places. Round answers to 3 decimal places)
The 90% confidence interval ______ to _______.
Given information-
Sample size, n = 16
Calculating sample mean and sample standard deviation using excel.
=AVERAGE(17:20)
And standard deviation-
=STDEV.S(17:20)
Sample mean, x-bar = 18.0714
Sample standard deviation, s = 3.8323
Confidence level, c = 0.90
So, significance level, α = 0.1
Since here population standard deviation is unknown so we will use t-distribution.
Now, degree of freedom is given by-
Degree of freedom, df = n - 1
Degree of freedom, df = 16-1 = 15
Step by step
Solved in 2 steps with 1 images
