Your client from question 4 decides they want a 90\% confidence interval instead of a 95\% one. You sampled 36 students to find out how many hours they spent online last week. Your sample mean is 46. The population standard deviation, \sigma, is 7.4. What is the 90\% confidence interval for this sample mean?

UkusakazaL

UkusakazaL

Answered question

2021-08-09

Your client from question 4 decides they want a 90% confidence interval instead of a 95% one. To remind you - you sampled 36 students to find out how many hours they spent online last week. Your sample mean is 46. The population standard deviation, σ, is 7.4. What is the 90% confidence interval for this sample mean? Keep at least three decimal places on any intermediate calculations, then give your answer rounded to 1 decimal place, with the lower end first then upper.
(_______ , ___________ )

Answer & Explanation

Ian Adams

Ian Adams

Skilled2021-08-16Added 163 answers

Step 1
Given,
sample size (n)=36
sample mean (x)=46
standard deviation (σ)=7.4
α=10.90=0.1
α2=0.05
Z0.05=1.645
Step 2
90% confidence interval (C.I.):X±Zα2×σn
C.I=46±1.645×7.436
C.I=46±2.029
C.I=(462.029,46+2.029)
C.I=(43.971,48.029)
C.I=(44.0,48.0)

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