A researcher knows that the weights of 6-year-olds are normally distributed with m = 20.9 kg and s = 3.2. She suspects that children in poverty-stricken regions are undernourished and therefore underweight. With a sample of n = 16 children, the researcher obtains a sample mean of M = 18.3. Use a one-tailed test with a = .01 to determine if the weights for this sample are significantly lower than what would be expected for the regular population of 6-year-olds. Include the null hypothesis in symbols, critical region(s), and a conclusion about significance

A researcher wants to select a sample from a population with a mean (µ)= 60 and administer a treatment to individuals in the sample. He thinks the treatment will help improve scores.             a.  State the hypotheses for a one-tailed test.            b. For a one-tailed test, would the critical region be located in the positive or right-hand tail of the distribution, or in the negative or left-hand tail of the distribution?

One sample has n=7 and SS=35 and a second sample has n =17 and SS =45. What is the pooled variance for these two samples?

A psychologist wants to test whether there is any difference in puzzle-solving abilities between boys and girls. Independent samples of eleven boys and seven girls were chosen at random. The boys took a mean of 37 minutes to solve a certain puzzle, with a standard deviation of 4.8 minutes. The girls took a mean of 35 minutes to solve the same puzzle, with a standard deviation of 4.5 minutes. Assume that the two populations of completion times are normally distributed, and that the population variances are equal. Can we conclude, at the 0.10 level of significance, that the mean puzzle-solving times for boys, μ1 is greater than the mean puzzle-solving times for girls, μ2? Perform a one-tailed test. Then complete the parts below. Carry your intermediate computations to three or more decimal places and round your answers as specified in the table. a. State the null hypothesis H0 and the alternative hypothesis H1. b. Find the value of the test statistic. (Round to three or more decimal…