When we want to estimate the mean of a population using a sample but do not know the population standard deviation which of the following steps are required select all that apply?

When we want to estimate the mean of a population using a sample but do not know the population standard deviation which of the following steps are required select all that apply?

When we want to estimate the mean of a population using a sample, but do not know the population standard deviation, which two of the following steps are required? Use the sample standard deviation as an estimate of the population standard deviation.

What is the point estimate for population mean and proportion?

The sample mean, x-bar, is the point estimate for the population mean; the sample proportion, p-hat, is the point estimate used to estimate the population proportion; and the standard error, s, is the point estimate for the population standard deviation. The accuracy point depends on reducing bias and variability.

Does population mean affect confidence interval?

Different investigators taking samples from the same population will obtain different estimates, and have different 95% confidence intervals. However, we know that for 95 of every 100 investigators the confidence interval will include the population mean interval.

What is the point estimate of the population mean?

A point estimate of a population parameter is a single value used to estimate the population parameter. For example, the sample mean x is a point estimate of the population mean μ.

How to estimate the proportion of the population?

If a normal model is a good fit for the sampling distribution, then about 95% of sample proportions estimate the population proportion within 2 standard errors. We say that we are 95% confident that the following interval contains the population proportion.

How is the distribution of sample proportions similar to the mean?

In this part you will learn about the distribution of sample proportions. In a sense, this is an exact repeat of the sampling distribution of the sample means. Whereas the mean of a population is obtained by averaging the value of interest, a proportion is simply the percent of a population that does or does not have a certain characteristic.

Why do we use standard error in estimating population proportion?

(Remember that the error here is due to chance. It is not due to a mistake that anyone made.) For a given sample proportion, we will not know the amount of error, so we use the standard error as an estimate for the average amount of error we expect in sample proportions.

When to use normal model for sample proportions?

Recall the two conditions for using a normal model for sample proportions: The sample must be random. The expected number of successes in the sample, np, and the expected number of failures, n (1 – p ), are both greater than or equal to 10. In symbols, this is np ≥ 10 and n (1 − p) ≥ 10.