A manufacturer of cell phones has decided that an assembly line will be considered to be operating satisfactorily if less than 0.02% of the phones produced per day are defective. To check the quality of a day's production, the company decides to randomly sample 40 phones from the day's production to test for defects. Three of the phones in the sample are defective.

a) Identify the population and the sample.
Is the parmaeter in the study known or unknown .. Explain

THIS WAS MY ANSWER a)Identify the population and the sample.

N (population) is ALL phones produced per day
n (sample) is 40 random phones from the day’s production

b) Is the population parameter in this study known or unknown? Explain.
UNKNOWN - Parameter is the numerical summary of the population. The population is the number off ALL phones only the sample number is stated 40.

a) The population in this study is all the cell phones produced by the manufacturer in a day, while the sample is the 40 phones randomly chosen from the day's production to test for defects.

The parameter in this study is unknown. The population proportion of defective phones in a day's production is the parameter the manufacturer is interested in, but it is not specified in the problem statement. It will be estimated using the sample proportion of defective phones.

In this case, the population refers to all of the phones produced by the manufacturer in a day. The sample, on the other hand, refers to the 40 phones that were randomly selected from the day's production.

The parameter in this study is the proportion of defective phones in the population. Specifically, it is the proportion of defective phones among all the phones produced in a day.

In this case, whether the parameter is known or unknown depends on the context. If the company has historical data or information about the proportion of defective phones, then the parameter might be known. However, if this is a new study or the company doesn't have such information, then the parameter would be unknown.