A researcher has access to 100 participants for an independent sample design study, and she is hoping to achieve power = .80.What effect size will her data need to achieve to make that possible?

A researcher conducted a one-way ANOVA to compare the depression levels of three treatment groups. He got the following sum of squares for each group: Group 1:  SS1 = 51;       Group 2:  SS2 = 48;       Group 3:  SS3 = 63. Calculate SSWithin.

Tardigrades, or water bears, are a type of micro-animal famous for their resilience. In examining the effects of radiation on organisms, an expert claimed that the amount of gamma radiation needed to sterilize a colony of tardigrades no longer has a mean of 1150 Gy (grays). (For comparison, humans cannot withstand more than 10 Gy.) A random sample of 25 tardigrade colonies found that the amount of gamma radiation needed to sterilize a colony had a sample mean of 1133 Gy, with a sample standard deviation of 02 Gy. Assume that the population of amounts of gamma radiation needed to sterilize a colony of tardigrades is appraximately normally distributed. Complete the parts below to perform a hypothesis test to see if there is enough evidence, at the 0.05 level af significance, to support that H, the mean amount of gamma radiation needed to sterilize a colony of tardigrades, is not equal to 1150 Cy. (a) State the null hypothesis H, and the alternative hypothesis H, that you would use for…

A standardized exam's scores are normally distributed. In a recent year, the mean test score was 1482 and the standard deviation was 315. The test scores of four students selected at random are 1910, 1200, 2210, and 1390. Find the z-scores that correspond to each value and determine whether any of the values are unusual. The z-score for 1910 is (Round to two decimal places as needed.)

A random sample of n1 = 157 people ages 16 to 19 were taken from the island of Oahu, Hawaii, and 12 were found to be high school dropouts. Another random sample of n2 = 129 people ages 16 to 19 were taken from Sweetwater County, Wyoming, and 6 were found to be high school dropouts. Do these data indicate that the population proportion of high school dropouts on Oahu is different (either way) from that of Sweetwater County? Use a 1% level of significance. (a) What is the level of significance?   (b)What is the value of the sample test statistic? (Test the difference p1 − p2. Do not use rounded values. Round your final answer to two decimal places.) (c) Find (or estimate) the P-value. (Round your answer to four decimal places.)

Education influences attitude and lifestyle. Differences in education are a big factor in the "generation gap." Is the younger generation really better educated? Large surveys of people age 65 and older were taken in n1 = 38 U.S. cities. The sample mean for these cities showed that x1 = 15.2% of the older adults had attended college. Large surveys of young adults (age 25 - 34) were taken in n2 = 37 U.S. cities. The sample mean for these cities showed that x2 = 18.1% of the young adults had attended college. From previous studies, it is known that ?1 = 6.4% and ?2 = 4.8%. Does this information indicate that the population mean percentage of young adults who attended college is higher? Use ? = 0.05. What is the value of the sample test statistic? (Test the difference ?1 − ?2. Round your answer to two decimal places.)=__(c) Find (or estimate) the P-value. (Round your answer to four decimal places.)=__

A researcher predicted that students will learn better if they attribute their performance to effort rather than natural ability. In one condition, a randomly selected group of sixth graders wrote an essay about a time when they worked hard to reach a goal. In a second condition, a different randomly selected group of sixth graders wrote about a skill they thought they were naturally good at. Afterwards, the students began a nine-week social studies unit that concluded with an achievement test. Use the data below to conduct an 1. appropriate statistical test (higher scores indicate higher achievement). Follow the 7 hypothesis testing steps you have been taught. Some of the steps have already been done for you. Wrote about Wrote about effort natural ability 81.89 M 84.77 40 55 60 60 1. Ho: There is no difference in the achievement scores of the students who wrote about effort and those who wrote about natural ability Mefort = Hability Ha: There is a difference in the achievement scores…

The chemical benzene is highly toxic to humans. However, it is used in the manufacture of many medicine dyes, leather, and coverings. Government regulations dictate that for any production process involving benzene, the water in the output of the process must not exceed 7,950 parts per million (ppm) of benzene. For a particular process of concern, the water sample was collected by a manufacturer 25 times randomly and the sample average x was 7960 ppm. It is known from historical data that the standard deviation o is 100 ppm. (a) What is the probability that the sample average in this experiment would exceed the government limit if the population mean is equal to the limit? (b) Is an observed x = 7960 in this experiment a firm evidence that the population mean for the process exceeds the government limit? Assume that the distribution of benzene concentration is normal.

Suppose that 73.2% of all adults with type 2 diabetes also suffer from hypertension. After developing a new drug to treat type 2 diabetes, a team of researchers at a pharmaceutical company wanted to know if their drug had any impact on the incidence of hypertension for diabetics who took their drug. The researchers selected a random sample of 1000 participants who had been taking their drug as part of a recent large-scale clinical trial and found that 718 suffered from hypertension. The researchers want to use a one‑sample ?z‑test for a population proportion to see if the proportion of type 2 diabetics who have hypertension while taking their new drug, ?p, is different from the proportion of all type 2 diabetics who have hypertension. They decide to use a significance level of ?=0.01α=0.01. Determine the value of the ?z‑test statistic. Give your answer precise to two decimal places. Determine the ?-valueP-value for this test. Give your answer precise to three decimal places.

A ski resort tracks the proportion of seasonal employees who are rehired each season. Rehiring a seasonal employee is beneficial in many ways, including lowering the costs incurred during the hiring process such as training costs. A random sample of 755 full-time and 415 part-time seasonal employees from 2009 showed that 419 full-time employees were rehired compared with 186 part-time employees. (a) Is there a significant difference in the proportion of rehires between the full-time and part-time seasonal employees? (Use α = 0.02.)   (a-1) Specify the decision rule. (A negative value should be indicated by a minus sign. Round your answers to 3 decimal places.) Reject the null hypothesis if zcalc > _____ or zcalc <  ______. (a-2) Find the test statistic zcalc. (Round intermediate calculations to 4 decimal places. Round your answer to 3 decimal places.) zcalc_______   (b) Find the p-value. (Round your answer to 4 decimal places.) p-value ______