Chapter 20 Assignment Make sure you name your document “Chapter 20_Your Last Nam

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Chapter 20 Assignment

Make sure you name your document “Chapter 20_Your Last Name.” For example “Chapter20_Rogers,” is how I would do it. This really helps me with grading more efficiently. You could also just copy and paste into the assignment if that is more convenient but please make sure to put the number of the question!

Write the null and alternative hypothesis for each study description. Use both symbols and words. Say whether the alternative hypothesis is non directional or directional.

1.       The general manager of SuperCold air conditioning company tells a reporter that at least 85% of its customers are satisfied with their SuperCold air conditioners. (16 points)

2.       In Philadelphia, an experiment was conducted to determine if large doses of Echinacea* prevented colds. Five hundred volunteers were randomly assigned to either a treatment group or a control group. Member of the treatment group were given a large daily dose of Echinacea, and if they felt they might be getting cold the dosage was increased. Those in the control group got nothing. (16 points)

*Echinacia is a plant that that is purported to boost the immune system and fight colds and other viruses.

3.       A non-profit organization claimed that the contents of 75% oatmeal packets produced by a well-known oats company have the same mass of oats as claimed on the packet . (16 points)

4.       A student adviser claimed that first year Spanish students spend on average of 1 hour per week doing homework exercises. (16 points)

5.       A company that has a 15% market share starts a marketing campaign because they want to increase their market share. At the end of the campaign, they conduct a study to determine whether, in fact, the market share has increased. (16 points)

6.       A bottling machine in a drink factory is set to automatically fill each bottle with 355 ml of soft drink. A quality control inspector takes random samples throughout the day to determine whether the machine should be adjusted. (16 points)

Explanation / Answer

1) Let p be the proportion of customers who are satisfied with the SuperCold airconditioners.

                 H0 : p 0.85 Null Hypothesis. At least 85% are satisfied with the SuperCold Air conditioners.

                 Ha : p < 0.85    Alternate Hypothesis. Less than 85% are satisfied with the SuperCold Air conditioners.

This is a directional test. (Single tail, Left tailed test)

2) Let be the population mean of people who got large doses of Echinacea if they thought they were getting a cold and be the population mean of people who got no dosage of Echinacea if they thought they were getting a cold.

     H0:   =       The Null Hypothesis. There is no difference in treatments for prevention of colds.

     Ha:      The Alternate Hypothesis. There is a difference in treatments for prevention of colds.

This is a Non Directional test (2 tailed test)

3) Let p be the proportion of packets in which the mass of oatmeal inside is equal to the mass of oatmeal printed on the packet.

H0 : p = 0.75 Null Hypothesis. The mass of oatmeal inside is the same as the value printed on the packet.

Ha : p 0.75 Alternate Hypothesis.The mass of oatmeal inside is not the same as the value printed on the packet

This is a Non Directional test (2 tailed)

4) Let be the mean of the population of first year Spanish students who spend 1 hour per week doing homework excercises.

H0:   = 1 hour   Null Hypothesis. Time spent on doing homework excercises by first year Spanish students is 1 hour.

Ha: 1 hour.      Alternate Hypothesis. Time spent on doing homework excercises by first year Spanish students is not equal to 1 hour.

This is a Non Directional test (2 tailed)

5) Let p be the market share of the company after the campaign.

H0 : p = 0.85    Null Hypothesis. There is no change in market share after the campaign.

Ha : p > 0.85    Alternate Hypothesis. There is an increase in market share after the campaign

This is a Directional test (1 tailed, right tailed test)

6) Let be the mean of the population of volumes of soft drink in each bottle filled in the drink factory

H0:   = 335ml Null Hypothesis. The volume of soft drink in the bottles is 335 ml. No Caliberation required.

Ha: 335 ml Alternate Hypothesis: The volume of soft drink in the bottles are not equal to 335ml. Caliberation is required.

This is a Non Directional Test.(2 tailed test)

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