Question

The weight of a USB flash drive is 30 grams and is normally distributed. Periodically, quality control inspectors at Dallas Flash Drives randomly select a sample of 17 USB flash drives. If the mean weight of the USB flash drives is too heavy or too light the machinery is shut down for adjustment, otherwise, the production process continues. The last sample showed a mean and standard deviation of 31.9 and 1.8 grams, respectively. Using a = 0.10, the critical t values are _______.

Answer 1

The critical t values are -1.746 and 1.746.

Explanation:

Given information:

The weight of a USB flash drive is 30 grams and is normally distributed.

Population mean = 30

Sample size = 17

Sample mean= 31.9

Standard deviation = 1.8

Significance level, α=0.10

Null hypothesis:
`H_0:\mu=30`

Alternative hypothesis:
`H_1:\mu\\eq 30`

It is a two tailed test.

The t-critical values for a two-tailed test, for a significance level of α=0.1 are -1.746 and 1.746.

Therefore the critical t values are -1.746 and 1.746.