All California 5th graders take a standardized test. The mean for the population of 5th graders is 68.9 and the standard deviation for the population is 10. What is the probability of randomly selecting a student who scored   a. ≥ 85? b. less than or equal to 85? c. between 80 & 85? d. between 60 & 85?

50 part-time students were asked how many courses they were taking this term. The (incomplete) results are shown below:  # of Courses Frequency Relative Frequency Cumulative Frequency 1 13     2 22     3       4 5       a. Complete the table above b. Find the sample mean and sample standard deviation. c.  How many standard deviations above or below the mean is taking three classes? d. Find the probability that someone takes at least 3 classes.

Please solve and code in R if possible.

In a city with three high schools, all the ninth graders took a Standardized Test, with these results: High School Mean score on test Number of ninth graders Glenwood 77 259 Central City 90 344 Lincoln High 66 171 The city's PR manager, who never took statistics, claimed the mean score of all ninth graders in the city was 77.7 . Of course, that is incorrect. What is the mean score for all ninth graders in the city? USE EXCEL. Round your answer to one decimal place.

The tourist bureau of the Caribbean Islands surveyed a sample of 5 United States tourists as they left to return home. The tourists were asked how many days they spent on their visits. Their responses were as follows. 6, 8, 10, 9, 7 Find the standard deviation of this sample of numbers. Round your answer to two decimal places.

You play a game of chance that you can either win or lose (there are no other possibilities) until you lose. Your probability of losing is p = 0.61. What is the probability that ita. takes 2 games until you lose. b. takes 5 games until you lose. c. Find the mean c. Find the standard deviation.

An Excel assignment counts for 0-10 points. The scores in a class of 12 students are recorded as follows:1 5 5 6 7 7 8 8 8 9 10 10 What is the deviation of the score 10 from the mean in 13a (recall that this involves a subtraction of the mean from the particular score)? I think I got answer but want to check.

Please answer within 30min thanks.

During an experiment, the following times (in seconds) were recorded. Find the mean. 6.3, 5.4, 6, 3.2, 5.4, 5.5 ... The mean is (Round to one decimal place as needed.) ...

Find the mean and standard deviation of the number of red-headed Scots in a randomly selected group of 155. The probability of having red hair is still 13% for Scottish people. a. Mean = b. Standard deviation (Round to 2 places)=