The Null and alternative hypotheses

For this assignment, you will read a few example studies and try to figure out the null and alternative hypotheses, and what the type I and type II errors would be in those situations.

Here’s an Example to give you an idea about what you’ll be doing: A researcher is interested in testing whether a new therapy for adolescent depression works to reduce depression. He measures depression before and after the therapy and he expects depression levels to decrease after therapy.

Hypotheses:

Null Hypothesis: H0: depression after therapy

depression before therapy (in other words, depression is the same or worse after therapy than it was before therapy);

Alternative Hypothesis: H1: depression after therapy < depression before therapy (in other words, depression is lower after therapy than it was before). This hypothesis is directional

· Type I error: The researcher concludes that depression decreases after therapy, when in reality depression is the same or worse after therapy (in other words, the researcher concludes that the therapy works to reduce depression, when in reality it did not!).

· Type II error: The concludes that depression levels are the same after therapy, when in reality they get better (in other words, the researcher concludes that the therapy did not work to reduce depression, when in reality it did!)

For some questions, you’ll get to choose from multiple choice options. For others, you’ll have to write out our own response.

Question 1

Scenario A. The manager at Dunder-Mifflin Paper Company interested in understanding if a company’s employee benefits increase employee satisfaction. In 2020 the company implemented a new benefits package that included optional benefits such as childcare, eldercare, and retirement packages. The manager compares the employee satisfaction ratings from before and after the new benefits package was implemented and expects that satisfaction will be higher after the new package is implemented. What is the null hypothesis for this scenario?

Group of answer choices

H0: satisfaction before the new package is implemented > satisfaction after the new package is implemented

H0: satisfaction before the new package is implemented

satisfaction after the new package is implemented

H0: satisfaction before the new package is implemented = satisfaction after the new package is implemented

H0: satisfaction before the new package is implemented

satisfaction after the new package is implemented

H0: satisfaction before the new package is implemented < satisfaction after the new package is implemented

Flag question: Question 2

Question 2

Group of answer choices

H1: satisfaction before the new package is implemented

satisfaction after the new package is implemented

H1: satisfaction before the new package is implemented < satisfaction after the new package is implemented

H1: satisfaction before the new package is implemented

satisfaction after the new package is implemented

H1: satisfaction before the new package is implemented > satisfaction after the new package is implemented

H1: satisfaction before the new package is implemented = satisfaction after the new package is implemented

Flag question: Question 3

Question 3

Flag question: Question 4

Question 4

Flag question: Question 5

Question 5

Scenario B. A researcher is interested in studying whether a new app can help improve first graders’ reading skills. She recruits two first grade classes from a local elementary school: classroom 1 uses the app for 30 minutes each day and classroom 2 does not use the app. She compares their reading ability at the end of the school year and expects reading ability to improve in the group that used the app. Is this a directional or non-directional hypothesis?

Group of answer choices

Non-Directional

Directional

Flag question: Question 6

Question 6

Flag question: Question 7

Question 7

Scenario B. A researcher is interested in studying whether a new app can help improve first graders’ reading skills. She recruits two first grade classes from a local elementary school: classroom 1 uses the app for 30 minutes each day and classroom 2 does not use the app. She compares their reading ability at the end of the school year and expects reading ability to improve in the group that used the app. What is the alternative hypothesis for this scenario?

Flag question: Question 8

Question 8

Group of answer choices

The researcher concludes that reading skills were the same for the group that used the app and for the group that did not use the app, when in reality the reading skills were the same for both groups.

The researcher concludes that reading skills were higher (better) for the group that used the app than for the group that did not use the app, when in reality the reading skills better for the group that used the app.

The researcher concludes that reading skills were the same for the group that used the app and for the group that did not use the app, when in reality the reading skills were better for the kids who used the app.

The researcher concludes that reading skills were higher (better) for the group that used the app than for the group that did not use the app, when in reality the reading skills were the same or worse for the kids who used the app.

Flag question: Question 9

Question 9

Scenario B. A researcher is interested in studying whether a new app can help improve first graders’ reading skills. She recruits two first grade classes from a local elementary school: classroom 1 uses the app for 30 minutes each day and classroom 2 does not use the app. She compares their reading ability at the end of the school year and expects reading ability to improve in the group that used the app What would be a type II error for this scenario?

Group of answer choices

Flag question: Question 10

Question 10

Scenario C. David sees an ad for a new kind of running shoe that promises to improve speed when running short distances. He decides to test this out. He compares his speed when running a mile with the new shoes to his speed when running a mile in the old shoes. His goal is to test whether the new shoes help him run faster.

Is this a directional or non-directional hypothesis?

Group of answer choices

Directional

Non-Directional

Flag question: Question 11

Question 11

Group of answer choices

H0: David will run the mile faster in the new shoes than with his old shoes.

H0: David will run the mile slower in the new shoes than with his old shoes.

H0: David will run the mile in the same amount of time or faster in the new shoes than with his old shoes.

H0: David will run the mile in the same amount of time the new shoes as with his old shoes.

H0: David will run the mile in the same amount of time or slower in the new shoes than with his old shoes.

Flag question: Question 12

Question 12

Group of answer choices

H1: David will run the mile at a different speed in the new shoes than with his old shoes.

H1: David will run the mile in the same amount of time or faster in the new shoes than with his old shoes.

H1: David will run the mile in the same amount of time or slower in the new shoes than with his old shoes.

H1: David will run the mile in the same amount of time new shoes as with his old shoes.

H1: David will run the mile faster in the new shoes than with his old shoes.

H1: David will run the mile slower in the new shoes than with his old shoes.

Flag question: Question 13

Question 13

0 words

Flag question: Question 14

Question 14

0 words

Flag question: Question 15

Question 15

Scenario D. A researcher is interested in examining if the amount of money spent on groceries purchased via Amazon Prime has changed in the last 2 years. Should we test this using a directional or non-directional hypothesis?

Group of answer choices

Non-Directional

Directional

Flag question: Question 16

Question 16

Scenario D. A researcher is interested in examining if the amount of money spent on groceries purchased via Amazon Prime has changed in the last 2 years. What is the null hypothesis for this scenario?

Group of answer choices

H0: The amount of money spent on groceries has not changed in the last 2 years.

H0: The amount of money spent on groceries has increased or stayed the same in the last 2 years.

H0: The amount of money spent on groceries has decreased or stayed the same in the last 2 years.

H0: The amount of money spent on groceries has changed in the last 2 years.

H0: The amount of money spent on groceries has increased in the last 2 years.

H0: The amount of money spent on groceries has decreased in the last 2 years.

Flag question: Question 17

Question 17

Scenario D. A researcher is interested in examining if the amount of money spent on groceries purchased via Amazon Prime has changed in the last 2 years. What is the alternative hypothesis for this scenario?

Group of answer choices

H1: The amount of money spent on groceries has changed in the last 2 years

H1: The amount of money spent on groceries has not changed in the last 2 years.

H1: The amount of money spent on groceries has decreased in the last 2 years.

H1: The amount of money spent on groceries has decreased or stayed the same in the last 2 years.

H1: The amount of money spent on groceries has increased or stayed the same in the last 2 years.

H1: The amount of money spent on groceries has increased in the last 2 years.

Flag question: Question 18

Question 18

Scenario D. A researcher is interested in examining if the amount of money spent on groceries purchased via Amazon Prime has changed in the last 2 years. What is a type I error for this scenario?

Group of answer choices

The researcher concludes that the amount of money spent on groceries is the same as it was 2 years ago, when in reality it has changed.

The researcher concludes that the amount of money spent on groceries has changed, when in reality it is not the same as it was 2 years ago.

The researcher concludes that the amount of money spent on groceries is the same as it was 2 years ago, when in reality it is the same as it was 2 years ago.

The researcher concludes that the amount of money spent on groceries has changed, when in reality it is the same as it was 2 years ago.

Flag question: Question 19

Question 19

Scenario D. A researcher is interested in examining if the amount of money spent on groceries purchased via Amazon Prime has changed in the last 2 years. What is a type II error for this scenario?

Group of answer choices

The researcher concludes that the amount of money spent on groceries is the same as it was 2 years ago, when in reality it is the same as it was 2 years ago.

The researcher concludes that the amount of money spent on groceries has changed, when in reality it is not the same as it was 2 years ago.

The researcher concludes that the amount of money spent on groceries has changed, when in reality it is the same as it was 2 years ago.

The researcher concludes that the amount of money spent on groceries is the same as it was 2 years ago, when in reality it has changed.

The Null and alternative hypotheses

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