A selection process to be set in a position in GM company. Candidates

jippie771h

jippie771h

Answered question

2021-12-04

A selection process to be set in a position in GM company. Candidates are requested to complete an aptitude test. The results from the test are assumed to follow a normal distribution with standard deviation, equal to 1.3. A simple random sample of 16 results from the test has a sample mean of 4.2.
You are given a confidence interval computed by a researcher for the preceding data, going from 3.83 to 4.57. Which confidence level was used to compute this interval?
1) 82.3%
2) 78.14%
3) 74.58%
4) 67.78%

Answer & Explanation

Mollicchiuk

Mollicchiuk

Beginner2021-12-05Added 13 answers

Step 1
According to given data:
The standard deviation: σ=1.3
Mean: μ=4.2
Sample: n=16
And the confidence interval: 3.83 to 4.57
The formula for confidence interval is:
Cl=μ±Z×σn
Where Z is a value corresponding to confidence level.
Step 2
So now put the maximum value in the CI formula:
4.57=4.2+Z(1.316)
4.57=4.2+Z(1.34)
Z(1.34)=4.574.2
Z(1.34)=0.37
Z=0.37(41.3)
Z=1.138
According to standard normal distribution table the Z value calculated above is corresponding to 74.58% confidence level.
Hence the option C is correct.

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