When the population standard deviation is not known what is used to estimate it?

When the population standard deviation is not known what is used to estimate it?

When the population standard deviation, σ, is unknown, the sample standard deviation is used to estimate σ in the confidence interval formula. The quantity 1.96σ/ √n is often called the margin of error for the estimate.

Which of the following two qualities are used to calculate the standard error of the mean?

c. The sample size and the sample standard deviation are the two key elements of the standard error of the mean.

What type of estimate states the range within which a population parameter probably lies?

1) (i) The interval estimate states the range within which a population parameter probably lies.

When referring to the normal probability function there is not just one of them there is a family of them?

When referring to the normal probability function, there is not just one of them; there is a “family” of them. The area under the normal curve within plus and minus one standard deviation of the mean is about 68%. The total area under the normal curve is 1.00.

When the population mean but not the population standard deviation is known which statistic is used to compare a sample to the population?

t-score test statistic
The result is a t-score test statistic. Because we do not know the population standard deviations, we estimate them using the two sample standard deviations from our independent samples.

When and the population standard deviation is not known what is the appropriate distribution?

t-distribution table
Main Point to Remember: You must use the t-distribution table when working problems when the population standard deviation (σ) is not known and the sample size is small (n<30). General Correct Rule: If σ is not known, then using t-distribution is correct.

Which of the following are used to calculate the standard error of the mean?

Write the formula σM =σ/√N to determine the standard error of the mean. In this formula, σM stands for the standard error of the mean, the number that you are looking for, σ stands for the standard deviation of the original distribution and √N is the square of the sample size.

When a range of values is used to estimate a population parameter?

interval estimate
interval estimate: A range of values used to estimate a population parameter.

When referring to the normal probability distribution there is not just one?

When referring to the normal probability distribution, there is not just one; there is a “family” of distributions. Some normal probability distributions have equal arithmetic means, but their standard deviations may be different.

How does standard deviation affect the size of a sample?

The variation in the population as measured by the standard deviation has little or no effect in determining the size of a sample selected from the population. The higher the degree of confidence, the larger the sample required to give a certain precision.

How do you find the standard deviation of a population?

To determine the size of a sample, the standard deviation of the population must be estimated by either taking a pilot survey or by approximating it based on knowledge of the population. The finite population correction factor is applied when the population size is known.

What is the mean of the sample means and population mean?

If 40 samples of size 21 were selected from a population of 22,493, we would expect the mean of the sample means and the population mean to be close but not exactly equal. In the sampling distribution of the sample means, the standard error of the mean will vary according to the size of the sample.

Why is there no error in predicting the population mean?

If the sample size keeps getting larger and larger and finally equals the size of the population, there would be no error in predicting the population mean because the sample size and the size of the population would be the same. The standard error of the mean will vary according to the size of the sample that is in the denominator.