BUSI 230 HW 9.2 Hypothesis Tests for a Population Mean, Standard Assignment solution answers

BUSI 230 HW 9.2 Hypothesis Tests for a Population Mean, Standard Deviation Known Assignment solutions complete answers 

 

Just put your values given and automatically provide answers for you!

 

The  is the probability, assuming  is true, of observing a value for the test statistic that is as extreme as or more extreme than the value actually observed.

 

The smaller the -value is, the stronger the evidence against the  hypothesis becomes.

 

A test is made of : 18 versus : . A sample of size n=53 is drawn, and x=20. The population standard deviation is =8.

(a) Compute the value of the test statistic. Round the answer to at least two decimal places.

Choose the correct type of hypothesis test. Then find the critical values for =0.05 and =0.01. Round your answers to three decimal places, if necessary.

Determine whether to reject .

 

Identify the following statements as true or false.

If P=0.05, the result is statistically significant at the =0.02 level.

If P=0.05, the null hypothesis is rejected at the =0.02 level.

If P=0.05, the result is statistically significant at the =0.10 level.

If P=0.05, the null hypothesis is rejected at the =0.10 level.

 

Facebook: A study showed that two years ago, the mean time spent per visit to Facebook was 20.2 minutes. Assume the standard deviation is =4.0 minutes. Suppose that a simple random sample of 107 visits was selected this year and has a sample mean of =19.2 minutes. A social scientist is interested to know whether the mean time of Facebook visits has decreased. Use the =0.10 level of significance and the P-value method with the TI-84 calculator.

(a) State the appropriate null and alternate hypotheses.

This hypothesis test is a

(b) Compute the P-value. Round the answer to at least four decimal places.

(c) Determine whether to reject . Use the  level of significance.

 

Calibrating a scale: Making sure that the scales used by businesses in the United States are accurate is the responsibility of the National Institute for Standards and Technology (NIST) in Washington, D.C. Suppose that NIST technicians are testing a scale by using a weight known to weigh exactly 1,000 grams. The standard deviation for scale reading is known to be =2.7. They weigh this weight on the scale 62 times and read the result each time. The 62 scale readings have a sample mean of x=1000.9 grams. The scale is out of calibration if the mean scale reading differs from 1,000 grams. The technicians want to perform a hypothesis test to determine whether the scale is out of calibration. Use the =0.01 level of significance and the P-value method with the TI-84 calculator.

State the appropriate null and alternate hypotheses.

Find the P-value. Round the answer to at least four decimal places.

 

Measuring lung function: One of the measurements used to determine the health of a person's lungs is the amount of air a person can exhale under force in one second. This is called the forced expiratory volume in one second, and is abbreviated FEV1. Assume the mean FEV1 for 10-year-old boys is 2.1 liters and that the population standard deviation is =0.4. A random sample of 63 10-year-old boys who live in a community with high levels of ozone pollution are found to have a sample mean FEV1 of 1.97 liters. Can you conclude that the mean FEV1 in the high-pollution community is less than 2.1 liters? Use the =0.10 level of significance and the P-value method with the TI-84 calculator.

State the appropriate null and alternate hypotheses.

Find the P-value. Round the answer to at least four decimal places.

 

Heavy children: Are children heavier now than they were in the past? The National Health and Nutrition Examination Survey (NHANES) taken between 1999 and 2002 reported that the mean weight of six-year-old girls in the United States was 49.3 pounds. Another NHANES survey, published in 2008, reported that a sample of 192 six-year-old girls weighed between 2003 and 2006 had an average weight of 48.2 pounds. Assume the population standard deviation is =14.3 pounds. Can you conclude that the mean weight of six-year-old girls in 2006 is different from what it was in 2002? Use the =0.10 level of significance and the P-value method with the TI-84 calculator.

Compute the P-value. Round your answer to at least four decimal places.