1. Question: True or False: The more samples taken in a scientific study, the longer the amount of time it will take to complete the research on the samples.Although there are other factors that affect study time, such as experience and equipment, increasing the number of samples will cause an increase in research time. 2. Question: Suppose that a large controlled experiment tests whether caffeine improves reaction times. A very large number of randomly selected participants are randomly given ...

If a regression analysis was to be completed on body mass index (BMI), what could be an independent variable in that analysis? Why? If we could, what other independent variables should be included in the analysis? What statistic(s) would show the value of that regression in understanding BMI?

1. Question: The table below shows data on annual expenditure, x (in dollars), on recreation and annual income, y (in dollars), of 20 families. Use Excel to find the best fit linear regression equation. Round the slope and intercept to the nearest integer. 2. Question: An economist is studying the link between the total value of a country's exports and that country's gross domestic product, or GDP. The economist recorded the GDP and Export value (in millions of $'s) for 30nations for the sam...

1. Question: A medical experiment on tumor growth gives the following data table……… The least squares regression line was found. Using technology, it was determined that the total sum of squares (SST) was 3922.8 and the sum of squares of regression (SSR) was 3789.0. Calculate R2, rounded to three decimal places. 2. Question: A scientific study on mesothelioma caused by asbestos gives the following data table……. Using technology, it was determined that the total sum of squares (SST) wa...

1. Question: The population standard deviation for the number of corn kernels on an ear of corn is 94 kernels. If we want to be 90%confident that the sample mean is within 17 kernels of the true population mean, what is the minimum sample size that should be taken? 2. Question: Suppose the scores of a standardized test are normally distributed. If the population standard deviation is 2 points, what minimum sample size is needed to be 90% confident that the sample mean is within 1 point of the t...

1. Question: Suppose an automotive repair company wants to determine the current percentage of customers who keep up with regular vehicle maintenance. How many customers should the company survey in order to be 90% confident that the estimated (sample) proportion is within 2 percentage points of the true population proportion of customers who keep up with regular vehicle maintenance? 2. Question: Suppose a shoe store wants to determine the current percentage of customers who are males. How many...

Confidence Intervals In everyday terms, a confidence interval is the range of values around a sample statistic (such as mean orproportion) within which clinicians can expect to get the same results if they repeat the study protocol orintervention, including measuring the same outcomes the same ways. As you ask yourself, "Will I get thesame results if I use this research?", you must address the precision of study findings, which is determined bythe Confidence Interval. If the CI around the sam...

1. Question - A statistics professor recently graded final exams for students in her introductory statistics course. In a review of her grading, she ... the mean score out of 100points was a x¯=77, with a margin of error of 10……Construct a confidence interval for the mean score (out of 100 points) on the final exam. 2. Question - A random sample of adults were ... whether they prefer reading an e-book over a printed book. The survey resulted in a sample proportion of p′=0.14, with a samp...

MATH 225N Week 7 Hypothesis Testing Q and A

1. Question: Suppose the germination periods, in days, for grass seed are normally distributed. If the population standard deviation is 3 days, what minimum sample size is needed to be 90% confident that the sample mean is within 1 day of the true population mean? 2. Question: The length, in words, of the essays written for a contest are normally distributed with a population standard deviation of 442 words and an unknown population mean. If a random sample of 24 essays is taken and results in ...