When do we use t vs. z distributions? What are assumptions that must be met when...
When do we use t vs. z distributions? What are assumptions that must be met when using the t distribution?
When can we assume equal population variances?
What are degrees of freedom? When do we need to calculate them?
What do we estimate when solving the formula for finding z obtained with sample proportions in the two sample case? How do we estimate it?
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When do we use t vs. z distributions? What are assumptions that
must be met when...
Use the Distributions tool to look at the t distributions for different sample sizes. To do this,...
Use the Distributions tool to look at the t distributions for different sample sizes. To do this, choose the Degrees of Freedom for the first sample size on the slider, and click the radio button with the single orange line. Move the orange vertical line to the right until the number below the orange line is located on the t statistic. The probability of getting that t statistic or one more extreme will appear in the bubble with the orange...
The higher the alpha level, a. the lower the probability of rejecting the null hypothesis. b....
The higher the alpha level, a. the lower the probability of rejecting the null hypothesis. b. the greater the probability of rejecting the null hypothesis. c. the larger the sample size has to be to reject the null hypothesis. d. the more desirable the two-tailed test. When solving the formula for finding Z(obtained) with sample proportions in the two-sample case, we must first estimate a. the population proportion. b. the critical region. c. the ratio of the sample proportions. d....
Given X, and x, distributions that are normal or approximately normal with unknown o, and on,...
Given X, and x, distributions that are normal or approximately normal with unknown o, and on, the value of t corresponding to X, - X, has a distribution that is approximated by a Student's t distribution. We use the convention that the degrees of freedom is approximately the smaller of n - 1 and n, - 1. However, a more accurate estimate for the appropriate degrees of freedom is given by Satterthwaite's formula: 2 2 xn2 522 +$22) d.f. z...
1. When do we use an independent groups t-test? a. b. c. d. When we are...
1. When do we use an independent groups t-test? a. b. c. d. When we are comparing means from one sample that has been measured twice. When we are comparing means from two different samples. When we are comparing a sample mean to a population mean. When we are comparing two population means. 2. Which of the following is true regarding the use of t-tests for true experiments versus quasi-experimental designs? a. b. We use the same t-test whether it...
1. For a T distribution with 10 degrees of freedom, what is the probability P(T < -1.372)? 1. We ...
1. For a T distribution with 10 degrees of freedom, what is the probability P(T < -1.372)? 1. We consider a sample of 11 being used in a hypothesis test. In a two-sided hypothesis test where we reject if the value of |To| > Ta/2 is -2.05. Do you reject the null hypothesis in this case (explain why)? What is the p- value in this case (you may use a range for the p-value)? 2. This time a sample size...
1. Fill in the blank. In a one-sample t-test, we use the _________ to estimate...
1. Fill in the blank. In a one-sample t-test, we use the _________ to estimate the population standard deviation in order to calculate the standard error. How do you find the degrees of freedom (df) for a one-sample t-test? a. N b. Calculate the standard deviation of the sample c. n-2 d. n-1 Which of the following influences the likelihood of obtaining significant results? a. The larger your estimated standard error, the more likely it will be to get...
When using Student's t to compute an interval estimate, Multiple Choice 4:20 we assume that the...
When using Student's t to compute an interval estimate, Multiple Choice 4:20 we assume that the samples are collected from normally distributed populations and use the z distribution we estimate the population standard deviation based on the sample standard deviation use the z distribution we assume that samples are collected from normally distributed populations and the estimate of the population Prev 11 of 13 Next >
The difference between the T distribution and the standard normal (z) distribution decreases as the degrees...
The difference between the T distribution and the standard normal (z) distribution decreases as the degrees of freedom increase. True False When estimating the number of responses to be collected in order to achieve a desired margin of error on a proportion, what value should be used for the population proportion if no estimate is available? Enter your answer as a decimal to 2 decimal places. A population is believed to have a standard deviation of 23.1. An analyst wants...
Sometimes we want a confidence level using the T-Distribution. What is t a/2 when there are...
Sometimes we want a confidence level using the T-Distribution. What is t a/2 when there are 34 degrees of freedom and the confidence level is 99%? For this problem, round your answers to 3 digits after the decimal point
Table VII provides a t-distribution when the population standard deviation (sigma) is unknown. What is the...
Table VII provides a t-distribution when the population standard deviation (sigma) is unknown. What is the degrees of freedom (df) for a sample size n = 20? 2 10 19 0 o 20
Use the Distributions tool to look at the t distributions for different sample sizes. To do this, choose the Degrees of Freedom for the first sample size on the slider, and click the radio button with the single orange line. Move the orange vertical line to the right until the number below the orange line is located on the t statistic. The probability of getting that t statistic or one more extreme will appear in the bubble with the orange...
Given X, and x, distributions that are normal or approximately normal with unknown o, and on, the value of t corresponding to X, - X, has a distribution that is approximated by a Student's t distribution. We use the convention that the degrees of freedom is approximately the smaller of n - 1 and n, - 1. However, a more accurate estimate for the appropriate degrees of freedom is given by Satterthwaite's formula: 2 2 xn2 522 +$22) d.f. z...
1. When do we use an independent groups t-test? a. b. c. d. When we are comparing means from one sample that has been measured twice. When we are comparing means from two different samples. When we are comparing a sample mean to a population mean. When we are comparing two population means. 2. Which of the following is true regarding the use of t-tests for true experiments versus quasi-experimental designs? a. b. We use the same t-test whether it...
1. For a T distribution with 10 degrees of freedom, what is the probability P(T < -1.372)? 1. We consider a sample of 11 being used in a hypothesis test. In a two-sided hypothesis test where we reject if the value of |To| > Ta/2 is -2.05. Do you reject the null hypothesis in this case (explain why)? What is the p- value in this case (you may use a range for the p-value)? 2. This time a sample size...
When using Student's t to compute an interval estimate, Multiple Choice 4:20 we assume that the samples are collected from normally distributed populations and use the z distribution we estimate the population standard deviation based on the sample standard deviation use the z distribution we assume that samples are collected from normally distributed populations and the estimate of the population Prev 11 of 13 Next >
Table VII provides a t-distribution when the population standard deviation (sigma) is unknown. What is the degrees of freedom (df) for a sample size n = 20? 2 10 19 0 o 20
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