Let X be the number of students absent from a randomly chosen class on any given day. The standard deviation of X is 1.15. If many classes were selected at random, which of the following would be the best interpretation of the value 1.15?

Assume that thermometer readings are normally distributed with a mean of 0degrees°C and a standard deviation of 1.00degrees°C. A thermometer is randomly selected and tested. (The given values are in Celsius​ degrees.)   Between -1.47and 1.76

Suppose that, for a certain mathematics class, the scores are normally distributed with a mean of 75 and a standard deviation of 9. The teacher wishes to give A's to the top 5% of the students and F's to the bottom 5%. The next 15% in either direction will be given B's and D's, with the other students receiving C's. Find the bottom cutoff for receiving an A grade. (You may need to use the standard normal distribution table. Round your answer to the nearest whole number.)

Suppose the mean and standard deviation of the GPAs at Tulane are Xbar = 2.899; and s = -0.753Charlie's GPA has a z-score of -0.140. What is Charlie's GPA?(Leave your answer to 2 decimals: ex: 1.23)

The average amount of money spent for lunch per person in the college cafeteria is $6.24 and the standard deviation is $2.05. Suppose that 6 randomly selected lunch patrons are observed. Assume the distribution of money spent is normal, and round all answers to 4 decimal places where possible.What is the distribution of ¯x?

A​ city's mean minimum daily temperature in February is 25°F.Suppose the standard deviation of the minimum temperature in February is 3°F and that the distribution of minimum temperatures in February is approximately Normal. What percentage of days in February has minimum temperatures below freezing (32°F)​? Round to the nearest integer as needed.

Suppose that a category of world class runners are known to run a marathon (26 miles) in an average of 146 minutes with a standard deviation of 13minutes. Consider 49 of the races.Let X = the average of the 49 races. Find the 60th percentile for the average of these 49 marathons. (Round your answer to two decimal places.)min

Assume that the readings at freezing on a batch of thermometers are normally distributed with a mean of 0°C and a standard deviation of 1.00°C. A single thermometer is randomly selected and tested. Find P42, the 42-percentile. This is the temperature reading separating the bottom 42% from the top 58%. P42 = °C

I'm having a hard time on this question. A single toss of a fair coin results in either 0 or 1 head, each with probability 1/2. Define H = number of heads obtained on a single toss. The mean of H is = 0.5 And the standard deviation of H is = 0.5. Suppose you toss a fair coin four times. Define T = total number of heads obtained. Find the mean and standard deviation of T.

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