Key Concepts in Hypothesis Testing and Research Design

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Arizona State University *

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300

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Statistics

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Jun 10, 2024

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Question 1 1.25 / 1.25 pts If you hypothesize that there will be a difference between patient satisfaction scores from hospital A and hospital B, but you do not hypothesize the direction, you would have: A non-directional research hypothesis A directional null hypothesis A null hypothesis A directional research hypothesis Question 2 1.25 / 1.25 pts In this figure, the shaded areas represent _____ . the region of non-rejection the null hypothesis the outliers the region of rejection Question 3 1.25 / 1.25 pts Researchers want to determine how many times per week people walk their dogs. They select a representative sample of 250 dog owners and ask them about their dog walking habits over the last year. What type of bias might be a problem?

Selection Desirability Recall Measurement Question 4 1.25 / 1.25 pts Sally wants to evaluate the level of attachment between mother and child pairs. She sets up a room with toys and books and observes the interactions between each mother and child pair. The air conditioner in the room is not working properly and the observation room is extremely hot. The temperature of the room is an example of ___________________. bias confounding sampling error an extraneous variable Question 5 1.25 / 1.25 pts Which of the following occurs when you reject the null hypothe sis when it is really true? Correct decision Type I error Power Type II error

Question 6 1.25 / 1.25 pts An endocrinologist has established group visits for her pregnant patients with diabetes. The average infant birthweight for patients who did not attend shared visits is 9.5 lbs. She hypothesizes that the average infant birthweight for patients who did attend shared visits will be different. Would you use a one-tail test or a two-tail test to test this hypothesis? Two-tail One-tail Question 7 1.25 / 1.25 pts An endocrinologist has established group visits for her pregnant patients with diabetes. The average fructosamine level for patients who did not attend shared visits is 195. She hypothesizes that the average fructosamine level for patients who did attend shared visits will be lower. Would you use a one-tail test or a two-tail test to test this hypothesis? One-tail Two-tail Question 8 1.25 / 1.25 pts A health-focused radio show wants to determine what percentage of people in the Phoenix area are taking cholesterol medication. They ask listeners to call in and report whether or not they are taking cholesterol medication. What type of bias might be a problem? Recall Measurement

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Desirability Selection Question 9 1.25 / 1.25 pts True or False, power is the ability of a study to find a difference if it actually exists. True False Question 10 1.25 / 1.25 pts True or False, we always test a null hypothesis against an alternative hypothesis. True False Question 11 1.25 / 1.25 pts True or False, a finding can be statistically significant, but not clinically significant. True False Question 12 1.25 / 1.25 pts

What is the critical value of a two-tailed test when alpha is .05 if the test statistic adheres to an asymptotic standard normal distribution. +/-2.575 +/-1.96 +/-1.645 +/-1.99 Question 13 1.25 / 1.25 pts If you hypothesize that there is only a positive or only a negative relationship between two variables, what type of test should you use? Two-tailed One-tailed ANOVA Cohen's d Question 14 1.25 / 1.25 pts The probability of failing to reject a null hypothesis when it is false is represented by ______________.

beta (β) alpha ( α) p-value test statistic Question 15 1.25 / 1.25 pts Which of the following is(are) true about confounding variables (choose one or more)? A confounding variable is associated with the exposure. A confounding variable is the same as an extraneous variable A confounding variable creates an association that is misleading. A confounding variable is associated with the outcome. Question 16 1.25 / 1.25 pts Which of the following statements about the p-value is true? A very small p-value allows us to say there is enough evidence to accept the p-value The p-value is the probability of the sample data arising by chance The p-value is the chance of getting an observed effect if the alternative hypothesis was true The p-value is the chance of getting an observed effect if the null hypothesis was true Question 17

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1.25 / 1.25 pts True or False, the alternative hypothesis states that there is no difference/no effect. True False Question 18 1.25 / 1.25 pts Below is a hypothesis. There are 5 qualities of a good hypothesis outlined in our lecture. Which of the following apply to the hypothesis below? (choose one or more) Research hypothesis: A new mother's stress will go down when she uses her infant's nap time to engage in deep breathing and light exercise . Stated in declarative form rather than a question Defines expected relationship between variables Brief and to the point Testable - includes variables that can be measured Question 19 1.25 / 1.25 pts A type II error is made when the null hypothesis is rejected when it is true the null hypothesis is not rejected when it is false

the alternative hypothesis is not rejected when it is false the alternative hypothesis is not rejected when it is true Question 20 1.25 / 1.25 pts What does Alpha represent? Hypothesis Power Confidence interval Significance Quiz Score: 25 out of 25 Quiz Which of the following is NOT considered an extraneous variable in a situation where a researcher is examining the effect of watching a scary movie on the sympathetic nervous system? Temperature of the room You Answered The research participant's mood (my answer) The researcher interacts with the women who watch the scary movie differently then the women who do not watch the scary movie

Correct Answer The participant is normally tachycardic and hypertensive Extraneous variables influence the outcome of an experiment and confounding variables are associated with both exposure and outcome, making the relationship look different than it really is Question 2 1 / 1 pts _____ is the degree of risk a researcher is willing to take that they will reject the null when it is true. power Correct! Type I error Type II error The power of a hypothesis test is the probability of rejecting the null hypothesis if the null is false. Alpha (AKA significance & Type I error) is the degree of risk a researcher is willing to take that they will reject the null when it is true. Beta (Type II error) is the risk of failing to reject the null when it is false. Question 3 0 / 1 pts 500 people are questioned from Boston, Massachusetts. Which of the following terms best represents this group? Population Correct Answer Sample You Answered

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Cluster (my answer) cohort The population reflects ALL possible subjects or cases of interest in the study. The sample reflects a subset of the population, less than the population. Since the population of Boston, Massachusetts is obviously greater than 500, the 500 people questioned represent a sample of the total population of Boston, Massachusetts. Question 4 1 / 1 pts ________ = 1-β Correct! power alpha significance The power of a hypothesis test is the probability of rejecting the null hypothesis if the null is false and finds a difference if it actually exists. It is calculated by 1-β. Question 5 1 / 1 pts A type I error is made when the alternative hypothesis is not rejected when it is true Correct! "the null hypothesis is rejected when it is actually true "

the null hypothesis is not rejected when it is false the alternative hypothesis is not rejected when it is false Type I error occurs if the null hypothesis is rejected when it is actually true and a Type II error occurs if the null hypothesis is not rejected when it is actually false Question 6 1 / 1 pts A research journal just did a 2-year study on the effects of yoga, exercise, and diet on weight loss for female adults. They only submit the significant results of the effects of exercise on weight loss. What type of bias might be a problem? Selection Correct! Publication Measurement Recall It is a known issue that nonsignificant results are not published as frequently as significant results. This publication bias is problematic for researchers as they cannot know about studies of interest that failed to reject the null. Question 7 1 / 1 pts What does the population reflect? Subjects or cases that returned the voluntary survey.

A subset of the population. Correct! All possible subjects or cases of interest. Subjects or cases that did not return the voluntary survey. The population reflects ALL possible subjects or cases of interest in the study. The sample reflects a subset of the population, less than the population. 5 numbers (sample) from a group of 25 numbers (a specific population) represent a smaller sample from the larger population. (Salkind, p. 41) Question 8 1 / 1 pts What is power NOT affected by? Effect size beta (β) Correct! Standard deviation Sample size Power is affected by effect size, sample size, level of significance, and power (chosen or implied β). Quiz Score: 6 out of 8 Question 1

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1 / 1 pts What is power affected by? Standard error Population mean Standard deviation Correct! Sample size Power is affected by effect size, sample size, level of significance, and power (chosen or implied β). Question 2 1 / 1 pts If alpha is set at 5% ( = 0.05), describe the relationship between the p-value and alpha in order to consider the results significant? p-value is equal to alpha Correct! p-value is less than alpha p-value is greater than alpha If alpha is set at 0.05 ( = 5%) and the p-value is less than alpha, the results are significant. If alpha is set at 0.05 ( = 5%) and the p-value is greater than the alpha value, the results are likely due to chance, and the test statistic falls within the 95% nonsignificant area of the curve. If the null hypothesis (a statement of equality) is true, the findings will be nonsignificant. If the null hypothesis is false there should be significant findings. Question 3

1 / 1 pts Alpha represents ______ the outcome Correct! the level of significance the test statistic the p-value An alpha value is a pre-determined, pre-research value that represents statistical significance. Statistical significance is [t]he degree of risk a researcher is willing to take that they will reject the null when it is true (a Type 1 error). Question 4 1 / 1 pts What is power NOT affected by? Effect size Sample size beta (β) Correct! Standard deviation Power is affected by effect size, sample size, level of significance, and power (chosen or implied β).

Question 5 1 / 1 pts _____is the ability of the test to discover a difference if one actually exists. hypothesis Correct! power error The power of a hypothesis test is the probability of rejecting the null hypothesis if the null is false and finds a difference if it actually exists. It is calculated by 1-β. Question 6 1 / 1 pts What does the population reflect? Subjects or cases that did not return the voluntary survey. Subjects or cases that returned the voluntary survey. Correct! All possible subjects or cases of interest. A subset of the population. The population reflects ALL possible subjects or cases of interest in the study. The sample reflects a subset of the population, less than the population. 5 numbers (sample) from a group of 25 numbers (a specific population) represent a smaller sample from the larger population. (Salkind, p. 41)

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Question 7 1 / 1 pts What value is alpha conventionally set at? 0.25, which equals 25% 0.10, which equals 10% .001 or 0.1% Correct! 0.05, which equals 5% Conventionally, we use an alpha = to .05, or a 5% chance of the statistic occurring if H0 is true. Most researchers use 5% as the cutoff." (HYPOTHESIS TESTING PP) The odds are against getting a significant result, with 95% due to chance/5% due to a significant result. However, if significance results, then the researcher may have found evidence to support the research hypothesis and refute the null. If the alpha is set too high, the researcher runs the risk of making a type 1 error (rejecting the null when the null is true) If the alpha is set too low, the researcher risks making a type II error (failing to reject the null when the null is false). Question 8 1 / 1 pts Who decides the alpha value in research? the government the teacher the study participants

Correct! the researcher The researcher decides the alpha value. Conventionally, we use an alpha = to .05, or a 5% chance of the statistic occurring if H0 is true. Most researchers use 5% as the cutoff." (HYPOTHESIS TESTING PP) The odds are against getting a significant result, with 95% due to chance/5% due to a significant result. However, if significance results, then the researcher may have found evidence to support the research hypothesis and refute the null. If the alpha is set too high, the researcher runs the risk of making a type 1 error (rejecting the null when the null is true) If the alpha is set too low, the researcher risks making a type II error (failing to reject the null when the null is false). Quiz Score: 8 out of 8

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