### Cmpare and contrast internal and external validity

Assignment Help Basic Statistics
##### Reference no: EM13577430

Quantitative Research Question:

Download G*Power and play around with it. See how changes in assumptions and parameters affect sample size estimates. https://www.gpower.hhu.de/

1. Compare and contrast internal and external validity. Describe and give examples of research questions for which external validity is a primary concern.

2. Describe and give examples of research questions in which internal validity is a primary concern.

3. Discuss strategies researchers use in order to make strong claims about the applicability of their findings to a target population.

4. Compare and contrast random selection and random assignment. Be sure to include a discussion of when you would want to do one or the other and the possible consequences of failing to do random selection or random assignment in particular situations.

5. Explain the relationship between sample size and the likelihood of a statistically significant difference between measured values of two groups. In other words, explain why, all else being equal, as sample size increases the likelihood of finding a statistically significant relationship increases.

6. Compare and contrast probability and non-probability sampling. What are the advantages and disadvantages of each?

7. Calculate the sample size needed given these factors:

• one-tailed t-test with two independent groups of equal size

• small effect size (see Piasta, S.B., & Justice, L.M., 2010)

https://www.sage-ereference.com.proxy1.ncu.edu/view/researchdesign/n58.xml

• alpha =.05

• beta = .2

• Assume that the result is a sample size beyond what you can obtain. Use the compromise function to compute alpha and beta for a sample half the size. Indicate the resulting alpha and beta. Present an argument that your study is worth doing with the smaller sample.

8. Calculate the sample size needed given these factors:

• ANOVA (fixed effects, omnibus, one-way)

• small effect size

• alpha =.05

• beta = .2

• 3 groups

• Assume that the result is a sample size beyond what you can obtain. Use the compromise function to compute alpha and beta for a sample approximately half the size. Give your rationale for your selected beta/alpha ratio. Indicate the resulting alpha and beta. Give an argument that your study is worth doing with the smaller sample.

9. In a few sentences, describe two designs that can address your research question. The designs must involve two different statistical analyses. For each design, specify and justify each of the four factors and calculate the estimated sample size you'll need. Give reasons for any parameters you need to specify for G*Power.

#### Questions Cloud

 Suppose the total market value of a company is 6 million : suppose the total market value of a company is 6 million and the total market value of its debt is 4 million the Colasuonno corporation has two divisions the west division : colasuonno corporation has two divisions the west division and the east division. the corporations net operating income Estimate the cost of equity based on the three most : assume you have researched the following financial data1 rd yield on the firmu2019s bonds 7.00 and the risk premium Suppose that contamination particle size in micrometers can : suppose that contamination particle size in micrometers can be modeled as fx 2x-3 for 1 gt x and fx 0for x lt 1.a Cmpare and contrast internal and external validity : quantitative research questiondownload gpower and play around with it. see how changes in assumptions and parameters The company has noncallable bonds which mature in 25 years : 1 the company has noncallable bonds which mature in 25 years have an 8.00 annual coupon a par value of 1000 and a A standard deck of cards contains 52 cards one card is : a standard deck of cards contains 52 cards. one card is selected from the deck.a compute the probability of randomly A firm has issued long-term bonds with a total market value : a firm has issued long-term bonds with a total market value of 50 million and these bonds currently earn an expected If a normal model can be used to model them what percent : in the last quarter of 2007 a group of 64 mutual funds had a mean return of 4.8 with a standard deviation of 5.5. if

### Write a Review

#### Test claim that with a single line waiting times vary less

The waiting times have a standard deviation of 4.9 minutes. Use a 0.025 significance level to test the claim that with a single line, waiting times vary less than with individual lines.

#### Probability that mean of a sample families in pounds

Assume the standard deviation of the distribution is 2.5 pounds. Find the probability that the mean of a sample of 55 families will be between 17 and 18 pounds.

#### Measurement pf a sample

Any value which is based on having measured a sample is called:

#### Problem related to national exercise rate

A researcher believes that the percentage of people who exercise in California is greater than the national exercise rate. The national rate is 20%. The researcher gathers a random sample of 120 individuals who live in the California and finds tha..

#### T-procedure to test hypotheses about mean of population

You are thinking of employing a t-procedure to test hypotheses about the mean of a population using a significance level of 0.05.

#### Determining normal distribution sat scores

The average score on math portion of SAT was 516 in 2002. Assume that the math score of all students taking the SAT 2002 were normally distributed with a mean of 516 and a standard deviation of 90.

#### Probability that randomly selected employee have salary

A standard deviation of \$5000. What is the probability that a randomly selected employee will have a starting salary of at least \$31ooo?

The same students increased their scores on a retest to: 85,79,75,95, and 84. At the 0.05 significance level, is the intervention plan helpful in increasing grades?

#### What percentage of jazz cds play between given minutes

Mean 52 and standard deviation 7; N(52, 7). According to the 68-95-99.7 rule, what percentage of jazz CDs play between 38 and 59 minutes?

#### Two way anova with interaction in statdisk

Set up the following null and alternative hypotheses for both factors and their interaction. You should have three verbal statements, not symbolized statements.

#### Determining scores of values of each expression

For following scores determine values of each expression:  X: 4, 2, 1, & 5. åX, åX 2 , (åX) 2 , å(X-1).

#### Find the z-score for each student

Find the z-score for each student. Assuming both tests measure the same kind of ability, which student had the higher score?