Distributions A and B have the same mean and range. The standard deviations of distribution A and distribution B are 15 and 5, respectively. We may conclude that: the scores in distribution B are grouped closer to the mean than the scores in distribution A. the scores in distribution A are grouped closer to the mean than the scores in distribution B. there are three times as many scores from −1 standard deviation to +1 standard deviation in distribution A. there is one-third as many scores from −1 standard deviation to +1 standard deviation in distribution A. We cannot conclude anything unless we know the value of the mean.

One of the z-score formulas will help on this question. Scores on the SAT test are normally distributed with a mean of 500 and standard deviation of 100 points. Pretend someone scored 400 on the math portion of the SAT test. What would be the z-score cut off for this score?     A. 1.0   B. -1.0   C. 0   D. 2.0

There are two national college-entrance examinations, the scholastic aptitude test (SAT) and the American College Testing program (ACT).  Scores on the SATs are approximately normal with mean 500 and standard deviation 100.  Scores on the ACTs are approximately normal with mean 18 and standard deviation 6. Use the links provided for the Normal  (Links to an external site.)calculator and the Inverse Normal  (Links to an external site.) calculator to help complete the problems, you do not need to do any work out by hand. (instructions on how to use these calculators can be found in the week 5 star on the home page)  a)  What percent of all SAT scores are above 600? b)  Which is the greater accomplishment, scoring 630 on the SAT or 22 on the ACT ? Explain your reasoning for your choice. c)  How high a score in the SAT is needed to place in the top 2.5%.

Suppose in 2000, the science scores for female students had a mean of 146 with a standard deviation of 35. Assume that these scores are normally distributed with the given mean and standard deviation.   _________________ of the female students scored between 76 and 216

Assume that we have made 10 repeated measurements of a quantity, and as a result the error assigned to the “best estimate” of the mean is 6. If we then expand our data set to a total of 20 measurements, the error in the mean will reduce to just 3. True or False

Determine if the following statements are true or false. a. Jane took a sample of n = 100 observations from a population with mean and standard deviation. Mike also took a sample of n = 200 observations from the same population. Then, Mike’s sample mean will be closer to the true population mean than Jane’s sample. b. Jane took a sample of n = 100 observations from a population with mean and standard deviation. Mike also took a sample of n = 200 observations from a population with mean and standard deviation 2. Then, the sample mean from Mike’s sample is more likely to be close to the true mean than the sample mean from Jane’s sample. That is, the probability that X is between 90% and 110% of mean is higher for Mike’s sample than for Jane’s sample.

Help me find which A,B,C, or D is the correct answer to the last part please. The brain volumes ​(cm3​) of 50 brains vary from a low of 904 cm3 to a high of 1490 cm3. Use the range rule of thumb to estimate the standard deviation s and compare the result to the exact standard deviation of 191.4 cm3​, assuming the estimate is accurate if it is within 15 cm3. The estimated standard deviation is 146.5 cm3.     A. The approximation is not accurate because the error of the range rule of​ thumb's approximation is greater than 15 cm3.   B. The approximation is not accurate because the error of the range rule of​ thumb's approximation is less than 15 cm3.   C. The approximation is accurate because the error of the range rule of​ thumb's approximation is greater than 15 cm3.   D. The approximation is accurate because the error of the range rule of​ thumb's approximation is less than 15 cm3.