A statistician selects a sample of 20 participants and makes the decision to retain the null hypothesis. He conducts the same study testing the same hypothesis with a sample of 100 participants and makes the decision to reject the null hypothesis. Provide a likely explanation for why the two samples led to different decisions.
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- An experiment compares the taste of instant coffee versus fresh brewed. Each subject tastes two unmarked cups of coffee – in random order – and states which he or she prefers. Of the 50 who participate, 19 (or 38%) prefer the instant coffee while the remaining 31 (or 62%) prefer the fresh brewed. Let pdenote the proportion of the population who prefer fresh-brewed over instant. We wish to test if people prefer fresh-brewed over instant. Which of the following are the appropriate null and alternative hypotheses? Hint: if people cannot tell the difference between fresh brewed and instant, what would that make the value of p be? The null hypothesis is H0: ["", "", "", ""] The alternative hypothesis is Ha:Solve the last question pleaseAn LED light bulb manufacturer claims that the average lifespan of its 60-watt LED light bulbs is 27,000 hours. A corporate watchdog group is suspicious of the company's claim and thinks that the true average lifespan of the 60- watt LED light bulbs produced by the company may be less than the advertised 27,000 hours. The group collected and tested a random sample of 211 light bulbs and found the average lifespan of the sample was 26,941 hours. Use the p-value method to test the hypothesis that the mean lifespan of this brand of 60-watt LED light bulb is less than 27,000 hours, using a = 0.1. Assume the standard deviation of the lifespan of all such light bulbs is known to be 370 hours. State the null and alternative hypothesis for this test. Ho: ? H₁: ? Determine if this test is left-tailed, right-tailed, or two- tailed. right-tailed two-tailed left-tailed Should the standard normal (z) distribution or Student's (t) distribution be used for this test? The Student's t distribution…
- Can you help me determine the test statistic, the P-value, and the conclusion for this hypothesis test?Determine if the samples are independent or related. Two formulations of a new whitening soap are compared to their whitening effect. A random sample of 40 potential users of the soap is selected. Each person uses a randomization mechanism to determine which formulation is applied on the left arm so that the other formulation is applied on the right arm. After two weeks, they measured the effect of each formulation.An environmentalist wishes to conduct a hypothesis test on the percentage of cars driven in the city that are hybrids. Is it sufficient for him to use a simple random sample of 173 cars if hybrids currently account for 8%of the car sales in the country and he claims that the percentage of hybrids in the city is higher than that?
- A researcher takes a sample of 50 individuals and administers a background check to identify the number of prior arrests for each person. For whatever reason, one person is removed from the analysis and another random person is selected to replace that person. Having no additional information, what is your best guess of the number of prior arrests experienced by the replacement person? Why?There is some research to indicate that different dog breeds differ in emotionality. To consider these differences, a researcher administers a standard test of emotionality to 3 breeds of dogs (German Shepherd, Cocker Spaniel, and Chihuahua), with 4 dogs from each breed being tested. Higher scores mean higher emotionality. The results for the emotionality test scores appear below. Using the 7 steps of hypothesis testing, test the idea that there are differences in emotionality based on dog breed using α = .05 Emotionality Scores for Dogs German Shepherd Cocker Spaniel Chihuahua 6 0 10 1 4 12 7 0 9 2 0 8 T = 16 T = 4 T = 39 Gt = 59 N = 12 ∑x2 = 495 4. Decision Rule (Be sure to include your critical value) 5. Do your calculations 6. Make your decision 7. State your results in a sentence. Report your results in APA style including a measure of effect size. Be sure to include descriptive statistics (M). 8. Given your decision in #7, would…A manufacturer of laptop computers claims that only 1% of their computers are defective. In a sample of 600 computers, it was found that 3% were defective. If the proportion of defectives were really only 1%, there would be than 1 chance in 1000 of getting such a large proportion of defective laptops in the sample. Is there statistically significant evidence against the manufacturer's claim? Why or Why not?
- several years ago, the Gallup Organization conducted a random survey of 1018 adults aged 18 or older living in the United States and asked if you had $1000 to spend. Do you think investing it in the stock market would be a good idea? The Gallup study concluded that 54% of those surveyed said they thought investing in the stock. Market was a good idea. A statician would like to take a random sample of 200 of those 1018 adults and ask them the same question again to see if people change their minds over time. Based on the Gallup survey a statician specs that 54% of their sample will say that investing $1000 in the stock market would be a good idea give or take 2.1% find the chance as a percentage that institutions random sample 51% or more of them would say that investing $1000 in the stock market is a good idea write your answer as a percentage.A graduate student believes that people consider faces with more contrast between lip color and skin tone as more feminine. She identifies the null hypothesis as: Ho: The level of contrast between lip color and skin tone does not affect how feminine a face is considered. She chooses a significance level of 0.05. After she collects the data and computes the sample statistics, it is time for her to make a decision about the null hypothesis. What are the two possible decisions that the graduate student can make? Check all that apply. There is not enough evidence to reject the hypothesis that the contrast between lip color and skin tone affects how feminine a face is considered. There is enough evidence to reject the hypothesis that the contrast between lip color and skin tone does not affect how feminine a face is considered. There is enough evidence to reject the hypothesis that the contrast between lip color and skin tone affects how feminine a face is considered. ☐ There is not enough…Determine whether the results appear to have statistical significance, and also determine whether the results appear to have practical significance. In a study of a birth sex selection method used to increase the likelihood of a baby being born female, 2031 users of the method gave birth to 995 males and 1036 females. There is about a 19% chance of getting that many babies born female if the method had no effect. Because there is a 19% chance of getting that many babies born female the method had no effect, the method couples would likely use a procedure that raises the likelihood of a baby born female from the approximately 50% rate expected by chance to the % produced by this method. (Round to the nearest integer as needed.) So, this method