Question

In: Statistics and Probability

6. A researcher wants to study a phenomena known to have an effect size of .50. a)...

6. A researcher wants to study a phenomena known to have an effect size of .50.

a) According to Cohen, this effect size would be described as

(1 point)

small
medium
large

Q38:

b) What power would the researcher be able to obtain if he did a two-tailed single sample t test at α = .05, with a sample size of 25? (2 points)

Q39: delta equals

Q40: Power equals

c) With the same test (and alpha at .05), how many subjects would the researcher need to obtain power of 0.95? (2 points)

Q41: delta equals

Q42: number of subjects

d) Interpret/discuss your answer to the above question. That is, what does power

equal to .95 mean in the context of testing a hypothesis? (1 point)

Q43: Interpret in words

Expert Solution

6)

a)

Cohen suggested that d= 0.5 represents a 'medium' effect size

Option B

38)

b)

we are allowed to solve one question only. already solved two here.

orchestra answered 2 years ago

You are a researcher who wants to study the effect of age on aggression. Your hypothesis...

You are a researcher who wants to study the effect of age on aggression. Your hypothesis is that children become less aggressive as they age. Design a hypothetical study to test this hypothesis. Choose one of the methodological designs discussed in the book and lecture. Be sure to explain why you chose your design over other designs.

A) Suppose that a medical researcher wants to explore whether there is an effect of age...

A) Suppose that a medical researcher wants to explore whether there is an effect of age in systolic blood pressure for males between 40 to 60 years old. To investigate the relationship, a random sample of 100 males between 40 to 60 years old were selected and their systolic blood pressure was recorded. Identify each of the following for this experiment. Subjects: Individuals between 40 to 60 years old Or Males between 40 to 60 years old Or Systolic blood...

A researcher wants to be sure that the sample in her study is not unrepresentative of...

A researcher wants to be sure that the sample in her study is not unrepresentative of the distribution of ethnic groups in her community. Her sample includes 450 European-Americans, 70 African-Americans, 55 Latinos, 32 Asian-Americans, and 150 people without any ethnicity designated. According to census records, her community population is 48% European-American, 12% African-American, 18% Latino, 9% Asian-American, and 13% people without any ethnicity designated. Is her sample unrepresentative of her community? Carry out the steps of hypothesis testing using...

In a study of the effect of size of team on the volume of communications within...

In a study of the effect of size of team on the volume of communications within the team, can a double-blind procedure be utilized? a single blind?

A researcher wants to determine whether or not a given drug has any effect on the...

A researcher wants to determine whether or not a given drug has any effect on the score of a human subject performing a task of ESP sensitivity. He randomly assigns his subjects to one of two groups. 900 subjects in group 1 (treatment group) receive the drug. In contrast, 1000 subjects in group 2 (control group) receive a placebo. For the drug group, the mean score on the ESP test was 15, SD=4. For the no-drug group, the mean =9,...

In a marketing study, the researcher wants to minimize the cost of interviewing. These interviews will...

In a marketing study, the researcher wants to minimize the cost of interviewing. These interviews will be done to households with children, without children, and to individuals during the day and during the night. The cost for each type of interview is presented in the following table: Category Cost per day Cost per night With children $1500 $1900 Without children $1200 $1550 Individual $1100 $1250 The sample size is 800 people. At least there must be 400 households with children....

In a study at a large hospital the researcher wants to assure that male nurses are...

In a study at a large hospital the researcher wants to assure that male nurses are adequately represented. At this hospital 5% of the nurses are male. The researcher separates the nurses into female and male hats. He draws 95 female names and 5 male names. This is an example of: Select one: a. Simple random sampling. b. Stratified random sampling. c. Multistage random sampling. d. Cluster sampling.

A researcher wants to study the effectiveness of medication and the time of day on alertness....

A researcher wants to study the effectiveness of medication and the time of day on alertness. 18 patients are randomly selected and three are assigned to each of six groups. Their alertness scores are listed on the table. Is there any difference in the mean score depending on 1) the type of treatment, 2) time, and 3) an interaction effect between treatment and time? Use an alpha level of .05. Time Morning Afternoon Evening Treatment A 12 13 11 15...

When a qualitative researcher sends preliminary findings to study participants for validation this is known as

A researcher wanted to study the effect of type of diet on weight gain in mice....

A researcher wanted to study the effect of type of diet on weight gain in mice. The researcher was interested in 3 specific diets: standard mouse chow diet, “junk” food diet, and an organic diet. A total of 54 mice were randomly assigned to receive one of the 3 types of diets (18 in each group). The outcome variable (response variable) was weight gain (in grams) over a 1 month period. The 3 data sets provided below are for the same...