We are interested in the average preferred keyboard height among all trained typ

Question

We are interested in the average preferred keyboard height among all trained typists. A random sample of 31 typists results in a 95% confidence interval (in cm.) of (79.3, 80.7). Tell whether each statement is true or false and write 1-2 sentences explaining your answer.

(a) 95% of all trained typists prefer a keyboard height between 79.3 cm. and 80.7 cm. Circle the correct answer: TRUE FALSE

Explanation:

(b) The the average preferred keyboard height among all trained typists is a random quantity and there is a 95% chance that it lies between 79.3 cm and 80.7 cm. Circle the correct answer: TRUE FALSE

Explanation:

(c) If 20 random samples are taken and the correct procedure is used to calculate a 95% confidence interval for each sample, then exactly 19 of these samples will result in a confidence interval containing the true average preferred keyboard height among all trained typists. Circle the correct answer: TRUE FALSE

Explanation:

Explanation / Answer

a)

false ; as it is a sample and not population therefore we can not conclude on basis of this that 95% of all trained typists prefer a keyboard height between 79.3 cm. and 80.7 cm.

b)

false ; as population mean is a fixed quantity therefore it can not exist with a chance or probability. chance is applied for a random variable only

c)

True ; cause if we go through same method and calculate confidence interval then 95% of these interval contains population mean as sample mean is unbaised estimator of population mean.

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