The heights of adult men in America are normally distributed, with a mean of 69.3 inches and a standard deviation of 2.64 inches. The heights of adult women in America are also normally distributed, but with a mean of 64.5 inches and a standard deviation of 2.53 inches. a) If a man is 6 feet 3 inches tall, what is his z-score (to two decimal places)? z = 2.16 b) What percentage of men are SHORTER than 6 feet 3 inches? Round to nearest tenth of a percent.

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general 10 months ago 8713

The mean score of adult men on a psychological test that measures "masculine stereotypes" is 4.88. A researcher studying hotel managers suspects that successful managers score higher than adult men in general. A random sample of 48 managers of large hotels has mean x-bar = 5.91. Assume the population standard deviation is sigma = 3.2.Using the null and alternative hypotheses that you set up in problem 5, the value of the test statistic for this hypothesis test is ______

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general 10 months ago 4757

A CI is desired for the true average stray-load loss ? (watts) for a certain type of induction motor when the line current is held at 10 amps for a speed of 1500 rpm. Assume that stray-load loss is normally distributed with σ = 2.8. (Round your answers to two decimal places.)(a)Compute a 95% CI for ? when n = 25 and x = 51.4.(_________________, __________________) Watts(b) Compute a 95% CI for ? when n = 100 and x = 51.4.(________________________ , _____________________) watts(c) Compute a 99% CI for ? when n = 100 and x = 51.4.(___________________________, _______________________) watts(d) Compute an 82% CI for ? when n = 100 and x = 51.4.(_________________________, ___________________________) watts(e) How large must n be if the width of the 99% interval for ? is to be 1.0? (Round your answer up to the nearest whole number.)

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general 10 months ago 9812

Find the t-coordinates of all critical points of the given function. Determine whether each critical point is a relative maximum, minimum, or neither by first applying the second derivative test, and, if the test fails, by some other method.f(t)= -3t^3+2ta.) f has (a relative maximum, relative minimum, or no relative extrema) at the critical point t=________ * (smaller t-value)b.) f has (a relative maximum, relative minimum, or no relative extrema) at the crtical point t=__________* (larger t-value)

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general 10 months ago 5016

The article "Plugged In, but Tuned Out" (USA Today, January 20, 2010) summarized data from two surveys of randomly selected kids ages 8 to 18. One survey was conducted in 1999 and the other was conducted in 2009. Data on the number of hours per day spent using electronic media, consistent with summary quantities given in the article, are below.time1999<-c(4, 5, 7, 7, 5, 7, 5, 6, 5, 6, 7, 8, 5, 6, 6)time2009<-c(5, 9, 5, 8, 7, 6, 7, 9, 7, 9, 6, 9, 10, 9, 8)Find the 99% confidence interval for the difference between the mean number of hours per day spent using electronic media in 2009 and 1999. Show all steps of the confidence interval. You may use the formula or R for calculations.

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general 10 months ago 8029

A technician compares repair costs for two types of microwave ovens (type I and type II). He believes that the repair cost for type I ovens is greater than the repair cost for type II ovens. A sample of 60 type I ovens has a mean repair cost of $⁢85.79, with a standard deviation of $⁢15.13. A sample of 56 type II ovens has a mean repair cost of $78.67, with a standard deviation of $⁢17.84. Conduct a hypothesis test of the technician's claim at the 0.1 level of significance. Let μ1 be the true mean repair cost for type I ovens and μ2 be the true mean repair cost for type II ovens.Step 1 of 4: State the null and alternative hypotheses for the test.Step 2 of 4: Compute the value of the test statistic. Round your answer to two decimal places.Step 3 of 4: Determine the decision rule for rejecting the null hypothesis H0. Round the numerical portion of your answer to three decimal places.Step 4 of 4: Make the decision for the hypothesis test. Reject or Fail to Reject Null Hypothesis

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general 10 months ago 5544