Question

CHECK ANSWERS! You should use a Z test because of the large sample size 30 < and we know the mean and the standard deviation. 6. The Graded Naming Test (GNT) requires respondents to name objects in a set of 30 black-and-white drawings. The test is often used to detect brain damage in the UK. The test begins with easy words like kangaroo, but gets progressively more difficult, ending with words like sextant. The GNT population average for adults in the UK is 20.4, with a standard deviation of 3.2. An American researchers wonders if the test is valid for use in the US, using the scoring system established in the UK. The American researchers administers the GNT to 26 American adults, who scored an average of 17.25. - You should use a-test because the sample size is -- we know the standard deviation and the mean. 7. Bardwell, Ensign, and Mills (2005) assessed the moods of 60 male US Marines following a month-long training exercise conducted in cold temperatures and at high altitudes. Negative moods, including fatigue and anger, increased substantially during training and lasted up to three months afterwards. You decide to replicate this study and measure anger for six male Marines after similar training. Their anger scores were: 14, 12, 13, 12, 14, and 15. The population mean anger score for adult men is 9.20. Do the Marines who underwent the training significant differ from average adult men on anger? . You should use the one sample t test because the sample size is small and because the population standard deviation is unknown and the mean is known. 8. A local small business owner wants to know if her employees are taking too many or too few paids days off (e.g., sick leave, vacation). She asks you to help her determine whether she currently is too generous or too stingy with the amount of time she lets employees take off with pay. The national average for paid days off is 15 days according to your internet research. Her eight employees reported the following number of paid days off in the last year: 10, 11, 8, 14, 13, 12, 12, and 27 days. You should use the one sample i test because the sample size is small and because the population standard deviation is unknown and we know the mean.

please tell me if its a z test ke t test and why it is :) thanks!

Answer 1

When we use Z-test and T-test:-

When population standard deviation ($\mathbf{\sigma}$) is known, then we use Z- test and if population standard deviation ($\mathbf{\sigma}$) is unknown, then we use t- test.

Answers.

1. You should use one sample t test because here mean ($\bar{x}$) is given but population standard deviation ($\sigma$) is unknown.

2. You should use One sample Z- test because here mean ($\bar{x}$) is given but population standard deviation ($\sigma$) is also known.

3. You should use One sample Z- test because here mean ($\bar{x}$) is given but population standard deviation ($\sigma$) is also known.

6. You should use One sample Z- test because here mean ($\bar{x}$) is given but population standard deviation ($\sigma$) is also known.

7. You should use one sample t test because here mean ($\bar{x}$) is given but population standard deviation ($\sigma$) is unknown.

8. You should use one sample t test beause here mean ($\bar{x}$) is given but population standard deviation ($\sigma$) is unknown.