If a treatment is expected to increase scores among a population with u= 20, then the alternative hypothesis is µwith treatment > 20.

A sample of n = 25 individuals is selected from a population with µ = 20. After a treatment is administered to the individuals, the sample mean is found to be M = 22 and sample variance is s2 = 125.   Which type of t-test would you conduct in this scenario? Conduct a hypothesis test to evaluate the significance of the treatment effect. Use a two-tailed test with α = .05. State the hypothesis, find the critical region, calculate your test statistic, and evaluate your hypothesis. Show all intermediary steps for your calculations. Calculate Cohen’s d to measure the size of the treatment effect. Describe whether this is a small, moderate or large effect.

When a researcher rejects the null hypothesis The obtained statistical value is larger than the critical value. The obtained statistical value is smaller than the critical value P-value is smaller than the significant level.

If a sample is an extreme result and is significant, it will fall in the critical region which indicates a sample mean of that magnitude is unlikely if the null hypothesis is true. True or false?

I want to assess whether or not a new drug meant to help with depression symptoms actually helps those with depression. I recruited 10 subjects with depression and measured the number of symptoms they have (baseline). I then give them the new drug and measure the number of depressive symptoms they have two weeks later (post). I want to test the hypothesis that receiving the new drug will decrease depressive symptoms. At an alpha of 0.05, please test this hypothesis.         What is the null hypothesis?   What is the alternative hypothesis?     Using baseline - drug, compute difference values for this questions’ data:   Baseline (# symptoms) Drug (# symptoms) Difference values 5 3 2 4 2 2 2 2 0 1 0 1 5 3 2 3 2 1 2 2 0 1 1 0 7 6 1 7 4 3         What is the mean of the difference values?   What is the standard deviation of the difference values?   What is the standard error of the…

It was reported that last year the average price of gallons of gasoline in a city X was $3.15. This year a  sample of 50 gas stations had an average price of $3.10 for a gallon. We assume that the population standard deviation of prices is $0.15. We are interested in determining whether this year's mean price is less than last year. Perform a hypothesis test at the level of significance α=0.05.

Suppose we want to assess the effect of a one-day SAT prep class at a 5% level of significance. Scores on the SAT writing exam can range from 200 to 800. A random sample of 50 students takes the SAT writing test before and after a prep class. We test the hypotheses: H0 : μ = 0 Ha : μ > 0 where µ is the mean of the difference in SAT writing scores (after minus before) for all students who take the SAT prep class. The sample mean is 5 with a standard deviation of 18. Since the sample size is large, we are able to conduct the T-Test. The T-test statistic is approximately 1.96 with a P-value of approximately 0.028. Explain ?

A researcher conducted a t-test for independent samples to evaluate the mean difference between two treatment conditions and obtained t(48) = 4.00. What would be the computed F, if the outcomes of this study were evaluated by one-actor ANOVA for independent samples?

To identify the correct Z(critical), it is important to determine whether the hypothesis test is one-tailed or two-tailed. The decision between a one- and two-tailed hypothesis is based on the researcher's expectations about the population from which the sample was selected. Many people believe that millennials are having more sex than people during the sexual revolution. You wonder whether the cohort currently in their twenties had sex at an earlier age than older generations. Assume that the the average age of first sexual intercourse is 17.4 years. You obtain a sample that yields a sample mean of X = 15.9 years. Let u denote the average age of first sexual intercourse. Formulate your null and research hypotheses by selecting the appropriate values in the dropdown menus that follow. Ho: (H₁: The test you conduct is test. Note: A one-tailed test is described as a lower-tailed test if the null hypothesis is rejected for values of the test statistic in the lower tail of its…

A random sample of 60 trials resulted in 18 successes. List the null and alternate hypothesis if you were to test the claim that the population proportion exceeds 20% at an ?=0.01.