be the random variable representing the mean time to complete the  10  reviews. Assume that the  10  reviews represent a random set of reviews. (a) What is the mean, standard deviation, and sample size? Mean = Standard Deviation = Sample Size = (b) Complete the distributions. Round all decimals to four decimal places. X∼ ( Number, Number)   X¯¯¯∼ ( Number, Number

In a large section of a statistics​ class, the points for the final exam are normally​ distributed, with a mean of 74 and a standard deviation of 8. Grades are assigned such that the top​ 10% receive​ A's, the next​ 20% received​ B's, the middle​ 40% receive​ C's, the next​ 20% receive​ D's, and the bottom​ 10% receive​ F's. Find the lowest score on the final exam that would qualify a student for an​ A, a​ B, a​ C, and a D. The lowest score that would qualify a student for an A is nothing. ​(Round up to the nearest integer as​ needed.) The lowest score that would qualify a student for a B is nothing. ​(Round up to the nearest integer as​ needed.) The lowest score that would qualify a student for a C is nothing. ​(Round up to the nearest integer as​ needed.) The lowest score that would qualify a student for a D is nothing. ​(Round up to the nearest integer as​ needed.)

In a large section of a statistics class, the points for the final exam are normally distributed, with a mean of 73 and a standard deviation of 8. Grades are assigned such that the top 10% receive A's, the next 20% received B's, the middle 40% receive C's, the next 20% receive D's, and the bottom 10% receive F's. Find the lowest score on the final exam that would qualify a student for an A, a B, a C, and a D. Click here to view Page 1 of the Standard Normal Table. Click here to view Page 2 of the Standard Normal Table. The lowest score that would qualify a student for an A is (Round up to the nearest integer as needed.)

Justin and Robbie are golfers. The distribution of Justin's golf scores has a mean of 225 and a standard deviation of 25. Robbie's golf score distribution has a mean of 240 and a standard deviation of 15. Both distributions are approximately normal and they are completely independent of each other. What is the closest probability that Justin will have a higher golf score than Robbie in a randomly selected golf round?

In a recent​ year, the mean test score was 1539 1539 and the standard deviation was 310 310. The test scores of four students selected at random are 1950 1950​, 1300 1300​, 2270 2270​, and 1430 1430. Find the​ z-scores that correspond to each value and determine whether any of the values are unusual

2000 freshmen at state university took a biology test. the scores were normally distributed with a mean of 70 and a standard deviation of 5. Use z scores. (1) the percent of students that scored less than 77

Dan is doing research on organic farming for an agricultural foundation. He has collected data on the number of oranges harvested from individual trees in two different orchards. In each orchard, the number of oranges harvested from each of 57 trees was recorded. The histograms below show the distributions of the two data sets. The means and standard deviations for the data sets are also given. Orchard 1 Orchard 2 25 25 20- 20- 15+ 15- 10+ 10+ 5+ 5+ 199.5 219.5 239.5 259.5 279.5 299.5 319.5 339.5 359.5 199.5 219.5 239.5 259.5 279.5 299.5 319.5 339.5 359.5 Orchard 1 mean: 275.1 oranges Orchard 2 mean: 274.9 oranges Orchard 1 standard deviation: 23.2 oranges Orchard 2 standard deviation: 47.9 oranges Dan wants to use the Empirical Rule to make some approximations about both data sets. Unfortunately, it is appropriate to use the Empirical Rule on only one of them! Answer the parts below to help Dan with his approximations. (a) Identify the data set for which it is appropriate to use the…

Two friends, Karen and Jodi, work different shifts for the same ambulance service. They wonder if the different shifts average different numbers of calls. Looking at past records, Karen determines from a random sample of 40 shifts that she had a mean of 5.1 calls per shift. She knows that the population standard deviation for her shift is 1.2 calls. Jodi calculates from a random sample of 31 shifts that her mean was 5.8 calls per shift. She knows that the population standard deviation for her shift is 1.4 calls. Test the claim that there is a difference between the mean numbers of calls for the two shifts at the 0.01 level of significance. Let Karen's shifts be Population 1 and let Jodi's shifts be Population 2.   Step 3 of 3 :   Draw a conclusion and interpret the decision.

In a large section of a statistics​ class, the points for the final exam are normally​ distributed, with a mean of 69 and a standard deviation of 9.Grades are assigned such that the top​ 10% receive​ A's, the next​ 20% received​ B's, the middle​ 40% receive​ C's, the next​ 20% receive​ D's, and the bottom​ 10% receive​ F's. Find the lowest score on the final exam that would qualify a student for an​ A, a​ B, a​ C, and a D