From a normally distributed population, a simple random sample of size 30 is taken. The mean of the sample is 144 and the standard deviation of the sample is 12.

Which interval is the 90% confidence interval for the population mean?

(142.4, 145.6)

(143.3, 144.7)

(140.4, 147.6)

(139.7, 148.3)

Question

From a normally distributed population, a simple random sample of size 30 is taken. The mean of the sample is 144 and the standard deviation of the sample is 12.

Which interval is the 90% confidence interval for the population mean?

(142.4, 145.6)

(143.3, 144.7)

(140.4, 147.6)

(139.7, 148.3)

Vocaloid · Answer

|dw:1575391497123:dw|

Vocaloid · Answer

the z-value for a 90% interval is 1.645

|dw:1575391541192:dw|

Vocaloid · Answer

plug your z-value, mean, SD, and sample size n into the CI formula