In a hypothesis test for the population mean, when the population standard deviation (�) is known your test statistic has a ______ distribution.
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In a hypothesis test for the population
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- The value of the ___________ is used to estimate the value of the population parameter.Listed in the accompanying table are waiting times (seconds) of observed cars at a Delaware inspection station. The data from two waiting lines are real observations, and the data from the single waiting line are modeled from those real observations. Assume that the two samples are independent simple random samples selected from normally distributed populations, and do not assume that the population standard deviations are equal. Complete parts (a) and (b). One Line Two Lines 64.1 733.6 64.3 865.2 157.2 605.8 215.8 1089.7 142.2 267.8 85.6 662.7 278.9 310.2 339.6 518.1 253.2 128.8 199.5 565.6 475.7 132.9 630.3 268.2 478.2 122.1 333.1 350.4 473.5 128.9 328.9 95.2 402.1 232.7 914.6 99.7 721.6 461.2 552.8 162.7 760.7 482.2 596.7 100.6 692.3 518.1 837.1 508.5 903.1 580.2IQ is normally distributed with a mean of 100 and a standard deviation of 15. The middle 50% of IQs fall between what two values? Lower ___ Upper ___
- esc Introduction A chain of restaurants has historically had a mean wait time of 9 minutes for its customers. Recently, the restaurant added several very popular dishes back to their menu. Due to this, the manager suspects the wait time, μ, has increased. He takes a random sample of 44 customers. The mean wait time for the sample is 9.6 minutes. Assume the population standard deviation for the wait times is known to be 3.3 minutes. Can the manager conclude that the mean wait time is now greater than 9 minutes? Perform a hypothesis test, using the 0.05 level of significance. (a) State the null hypothesis Ho and the alternative hypothesis H₁. Ho: O H₁:0 (b) Perform a Z-test and find the p-value. Here is some information to help you with your Z-test. The value of the test statistic is given by Standard Normal Distribution Step 1: Select one-tailed or two-tailed. O One-tailed O Two-tailed Explanation μ Check □<口 X X OSO 020 0=0 x-H √n • The p-value is the area under the curve to the right…rary > MAT 240: Applied Statistics home > pothesis tests for the difference between two population means A company that develops an automated customer service model is interested in knowing whether two versions, Version A and Version B, will get different ratings from customers. Participants in a focus group are taken through samples from both versions, then take a survey to rate each version. A summary of the data obtained from the study is given below. Assume ratings from the different surveys generally have the same standard deviation. Version A Version B Mean 39.333 34.4 Observations Pearson Correlation -0.011 0 Hypothesized Mean Difference -2.086 P(T HDoes color enhance creativity? Test the indicated claim about the standard deviations or variances of two populations. Subjects are given a creativity exercise on a computer with either a red background or a blue background. The scores are shown in the table. At the 0.05 significance level, test the claim that those tested with red background have creativity scores with a standard deviation equal to the standard deviation for those tested with a blue background. Red Background Blue Background n1 = 39 n2 = 34 xˉx̄1 = 19.6 xˉx̄2 = 20.5 s1 = 0.72 s2 = 0.01 What are the correct hypotheses? (Select the correct symbols and use decimal values not percentages.)H0: Select an answer x̄₂ x̄₁ μ(red) p₂ p μ₁ μ₂ σ₁ s₁² σ(red) p₁ μ p̂₁ ? ≠ < > ≤ ≥ = Select an answer μ₁ μ₂ p₁ μ(blue) p σ₂ p₂ σ(blue) s₁² x̄₁ x̄₂ μ p̂₁ H1: Select an answer μ σ₁ x̄₁ μ(red) p̂₂ p₁ s₂² p₂ μ₂ μ₁ σ(red) x̄₂ p ? ≤ ≥ ≠ > = < Select an answer μ(blue) σ(blue) p μ μ₁ p₁ x̄₂ s₁² x̄₁ σ₂ p̂₁ p₂ μ₂…
- Which of the following is not one of the assumptions of the t-test for independent samples? The populations of raw scores form at least a roughly normal distribution. They can only be done on Tuesdays. There is homogeneity of variance. There are two independent samples of interval/ratioscores.Cell Phone Lifetimes A recent study of the lifetimes of cell phones found the average is 23.8 months. The standard deviation is 5.8 months. If a company provides its 33 employees with a cell phone, find the probability that the mean lifetime of these phones will be less than 23.8 months. Assume cell phone life is a normally distributed variable, the sample is taken from a large population, and the correction factor can be ignored. Use a TI-83 Plus/TI-84 Plus calculator. Round your answer to at least four decimal places. <PX23.8)=4000 B.C. A.D. 150 A study was done on skull sizes of humans during different time periods. The results are shown in the table. Assume that the two samples are independent simple random samples selected from normally distributed populations, and do not assume that the population standard deviations are equal. Complete parts (a) and (b) below. H2 27 27 131.05 mm 133.94 mm S 5.18 mm 5.27 mm a. Use a 0.05 significance level to test the claim that the mean skull breadth in 4000 B.C is less than the mean skull breadth in A.D 150. What are the null and alternative hypotheses? O B. Ho: H1 =H2 O A. Ho: H1 =H2 H:H1> H2 OC. Ho: H1 = H2 H1: H1 # H2 O D. Ho: H1 # H2 H: H1
