Find a. the mean; b. the deviation from the mean for each data item; and c. the sum of the deviations in part (b) for the following group of data items. \( 2.30,2.85,2.40,2.20,3.00 \) a. The mean is \( \square \). (Round to two decimal places as needed.)

What is the main goal of hypothesis testing in statistics? A To prove that the null hypothesis is true. B To determine whether there is enough evidence to reject the null hypothesis. (C) To calculate the mean of the population. (D) To verify the accuracy of the sample data.

standard deviation 3 a normal distribution random variable with mean 23 and that the probability \[ P(X>x)=0.66 \]

In a one-sample t-test, which of the following is true about the null hypothesis? (B) The sample mean is greater than the population mean (C) The sample mean is not equal to the population mean (D) The sample size is larger than 30

A group of researchers are investigating how different studying strategies impact how much participants remember on a test. They recruit 50 participants and have half of the participants study by just reading a passage over and over for 10 minutes. The other half of the participants spend five minutes reading the passage one time and then answering a series of multiple-choice questions on the material for another five minutes. Finally, the participants write down as many facts from the reading passage as they can in three minutes. Which of the following is the dependent variable of the study? (A) Whether they re-read the passage or tested themselves on the material (D) The number of participants in the study

Data from the Office for National Statistics show that the mean age at which men in Great Britain get married was 32.5 . A news reporter noted that this represents a continuation of the trend of waiting until a later age to wed. A new sample of 47 recently wed British men provided their age at the time of marriage. This data is contained below. Age- \( 26,36,27,30,28,26,36,33,25,30,31,34,26,33,29,32,30,39 \), \( 34,27,30,30,35,26,28,29,36,28,28,26,38,25,35,40,26,35,35,27 \), \( 33,29,28,33,38,39,35 \) Do these data indicate that the mean age of British men at the time of marriage exceeds the mean age in 2013 ? Test this hypothesis at a= 0.01. What is your conclusion? Use the obtained rounded values in your calculations. Sample mean: Sample standard deviation: t-value: p-value (Upper Tail):