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Vlad [161]
1 year ago
7

A psychologist is collecting data on the time it takes to learn a certain task. For 50 randomly selected adult subjects, the sam

ple mean is 16.40 minutes and the sample standard deviation is 4.00 minutes. Construct the 95 percent confidence interval for the mean time required by all adults to learn the task. Assume that X, the time to learn a task, is distributed normally.
Mathematics
1 answer:
tatuchka [14]1 year ago
8 0

Answer: (15.263,\ 17.537)

Step-by-step explanation:

According to the given information, we have

Sample size : n= 50

\overline{x}=16.40

s=4.00

Since population standard deviation is unknown, so we use t-test.

Critical value for  95 percent confidence interval  :

t_{n-1,\alpha/2}=t_{49, 0.025}= 2.009575\approx2.010

Confidence interval : \overline{x}\pm t_{n-1, \alpha/2}\dfrac{s}{\sqrt{n}}

16.40\pm (2.010)\dfrac{4}{\sqrt{50}}\\\\=16.40\pm1.13702770415\\\\=16.40\pm1.1370\\\\=(16.40-1.1370,\ 16.40+1.1370)\\\\=(15.263,\ 17.537)

Required 95% confidence interval :  (15.263,\ 17.537)

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