A research study was conducted about gender differences in "sexting." The researcher believed that theproportion of girls involved in “sexting” is less than the proportion of boys involved. The data collected in thespring of 2010 among a random sample of middle and high school students in a large school district in thesouthern United States is summarized in Table. Is the proportion of girls sending sexts less than the proportionof boys "sexting?" Test at a 1% level of significance.Table 2: Frequency of "sexts" sent by genderGenderMales FemalesSent "sexts"183 156Total number surveyed 2231 2169

Solution:- from given information claim: The proportion of girls sending sexts is less than the…

Answered: A research study was conducted about…

A First Course in Probability (10th Edition)

10th Edition

ISBN:9780134753119

Author:Sheldon Ross

Publisher:Sheldon Ross

Chapter1: Combinatorial Analysis

Section: Chapter Questions

Problem 1.1P: a. How many different 7-place license plates are possible if the first 2 places are for letters and...

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Labor Day was created by the U.S. labor movement over 100 years ago. It was subsequently adopted by most states as an official holiday. In a poll by Gallup, 1000 randomly selected adults were asked whether they approve of labor unions; 650 said yes. In 1936, about 72% of Americans approved of labor unions. At a 5% level of significance, do the data provide sufficient evidence to conclude that the percentage of Americans who approve of labor unions now has decreased since 1936? Solve using the critical-value approach. Define the parameter we are testing and setup a hypothesis test to see if less than 72% of Americans approve of labor unions currently. Calculate the test statistics for this hypothesis test. What is the critical value for this hypothesis test?
In a study examining the relation of math ability to the belief that math ability was innate, the belief was considered the predictor variable. The researcher hopes to find a correlation between the participants’ math ability and their belief that math ability is innate. The scores for the three participants are shown below. The group that believed that math is NOT innate scored 66, 70, 50. The group that believed that math IS innate scored 7, 4,10. what are the mean and SD for each group?
A researcher conducts an independent-measures study to examine how the brain chemical serotonin is related to aggression. One sample of rats serves as a control group and receives a placebo that does not affect normal levels of serotonin. A second sample of rats, low serotonin group, receives a drug that lowers brain levels of serotonin. Then, the researcher tests the animals by recording the number of aggressive responses each of the rats display. See the data below. Is there a significant difference between the control group and the low serotonin group regarding the number of aggressive responses? Control Low Serotonin n = 10 n = 15 M = 14 M = 19 SS = 180.5 SS = 130 Perform a hypothesis test using independent-measures t-test. Use a two-tailed…
Studies indicate that excessive noise at night can affect weight gain. One study of n = 127 rats compared the weight gain of rats exposed to excessive noise at night and the weight gain of rats in a quiet night environment. Sample statistics for the study are given in the table below. Use this information to determine if there is significant evidence that weight gain of rats exposed to excessive noise at night is different on average than weight gain of rats in a quiet night environment. Excessive noise at night environment (Group 1) Quiet night environment (Group 2) Sample mean (grams) 22.4 19.9 Sample standard deviation (grams) 6.4 3.8 Observations/Sample size 69 58 The 95% confidence interval for the difference (Group 1 – Group 2) in weight gain of rats exposed to excessive noise at night and rats in quiet night environment is (0.7g, 4.3g). Interpret this confidence interval in one or two sentences.
According to the most recent General Social Survey, 70% of adults watch TV nightly. A researcher believes that the proportion of college students who watch TV nightly is less than this. To test this claim the research samples 400 college students and finds that 276 watch TV nightly. At the 0.05 level of significance does this data provide evidence to suggest that the proportion of college students who watch TV nightly is less than 70%?
The accompanying table gives amounts of arsenic in samples of brown rice from three different states. The amounts are in micrograms of arsenic and all samples have the same serving size. The data are from the Food and Drug Administration. Use a 0.05 significance level to test the claim that the three samples are from populations with the same mean. Do the amounts of arsenic appear to be different in the different states? Given that the amounts of arsenic in the samples from Texas have the highest mean, can we conclude that brown rice from Texas poses the greatest health problem? Click the icon to view the data. Arsenic Amounts Arkansas California Texas Determine the test statistic. 4.81 4.91 5.02 5.44 5.44 5.42 5.63 5.61 5.63 5.86 5.96 6.06 1.45 3.66 4.04 4.49 4.93 5.08 5.29 5.43 5.42 5.46 5.58 5.55 5.57 5.78 6.64 6.93 6.89 6.85 7.09 7.30 7.49 7.55 7.71 7.72 The test statistic is (Round to two decimal places as needed.) Print Done
Studies indicate that excessive noise at night can affect weight gain. One study of n = 127 rats compared the weight gain of rats exposed to excessive noise at night and the weight gain of rats in a quiet night environment. Sample statistics for the study are given in the table below. Use this information to determine if there is significant evidence that weight gain of rats exposed to excessive noise at night is different on average than weight gain of rats in a quiet night environment. Excessive noise at night environment (Group 1) Quiet night environment (Group 2) Sample mean (grams) 22.4 19.9 Sample standard deviation (grams) 6.4 3.8 Observations/Sample size 69 58 The p-value for this test is 0.0086. Make a decision and conclusion for the hypothesis test in context. Use a 5% significance level (α = 0.05).
In the US, 45.1% of all people have type O blood, 39.6% have type A blood, 10.9% have type B blood and 4.4% have type AB blood. A researcher wants to see if the distribution of blood type is different for millionaires. The table below shows the results of a random sample of 614 millionaires. What can be concluded at the significant level of a = 0.05. For this study, we should use Chi-Square test for Goodness of Fit Your friend Caroline helped you with the null and alternative hypotheses... Ho : The distributions of blood types are the same between the general population and the millionaires. Ha: The distributions of blood types are NOT the same between the general population and the millionaires. You drew 614 samples, and the observed frequencies are recorded below. Please complete the table (round answers to at least 4 decimal places). Blood Type 0 A B AB Observed Count 274 230 57 53 Expected Count Click Download CSV to download csv file of data or copy/paste the data into Excel.…
In 1990, 58% of Americans 18 years old and older reported they have a great deal of concern regarding air pollution. A recent poll found that 592 of 1004 Americans 18 years old or older stated that they have a great deal of concern regarding the level of air pollution in American. Is there evidence to conclude that the current proportion of Americans having a great deal of concern about the level of air pollution in America is different from the 1990 proportion, with a 10% level of significance? State the null hypothesis, alternative hypothesis, test statistic, p-value and conclusion.
The Bureau of Labor Statistics reports that the official unemployment rate for Black people was 10.4% and 4.7% for White people in February 2015. Select all correct answers for this question. O The samples of white and black people are independent. The explanatory variable is the unemployment rate. The response variable is the unemployment rate. The response variable is race.
Studies indicate that excessive noise at night can affect weight gain. One study of n = 127 rats compared the weight gain of rats exposed to excessive noise at night and the weight gain of rats in a quiet night environment. Sample statistics for the study are given in the table below. Use this information to determine if there is significant evidence that weight gain of rats exposed to excessive noise at night is different on average than weight gain of rats in a quiet night environment. Excessive noise at night environment (Group 1) Quiet night environment (Group 2) Sample mean (grams) 22.4 19.9 Sample standard deviation (grams) 6.4 3.8 Observations/Sample size 69 58 Is this a one-tailed or a two-tailed test? Explain in one or two sentences.
One study found a negative correlation between participant’s age and hours of sleep they got (as they got older, they slept less). Which additional fact would lead you to believe that the relationship between age and hours of sleep is one of causation and not correlation? Jim is 63 and sleeps more than he did when he 47. Josie is 40 and sleeps fewer hours than when she was 30. The participants were randomly selected, the sample size was large, and the participants did not know the goal of the study. Jennie sometimes has difficulty sleeping.

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