Ten water samples are taken from a river: readings of contaminants in each sample are shown: 6, 8, 3, 7, 8, 7, 5, 4, 6, 9. The samples are known to be a normal distribution with mean 7,5 and standard deviation is 2.1. (a) Compute the probability that the reading of a sample is larger than 8 (b) Compute the probability that the sample mean is larger than 8

Service time for a customer coming through a checkout counter in a retail store is a random variable with the mean of 4.0 minutes and standard deviation of 2.0 minutes. Suppose that the distribution of service time is fairly close to a normal distribution. Suppose there are two counters in a store, n₁ = 46 customers in the first line and n₂ = 52 customers in the second line. Find the probability that the difference between the mean service time for the shorter line X₁ and the mean service time for the longer one X₂ is more than 0.3 minutes. Assume that the service times for each customer can be regarded as independent random variables. Round your answer to two decimal places (e.g. 98.76). P = !

The percent of fat calories that a person consumes each day is normally distributed with a mean of about 35 and a standard deviation of about ten. Suppose that 9 individuals are randomly chosen. Let X = average percent of fat calories. For the group of 9, find the probability that the average percent of fat calories consumed is more than six. (Round your answer to four decimal places.)

Service time for a customer coming through a checkout counter in a retail store is a random variable with the mean of 3.5 minutes and standard deviation of 3.5 minutes. Suppose that the distribution of service time is fairly close to a normal distribution. Suppose there are two counters in a store, n₁ = 2 customers in the first line and n₂ = 13 customers in the second line. Find the probability that the difference between the mean service time for the shorter line X₁ and the mean service time for the longer one X₂ is more than 0.1 minutes. Assume that the service times for each customer can be regarded as independent random variables. Round your answer to two decimal places (e.g. 98.76). P =

Suppose that the distribution of the grades of students in MAPEH performance 1 is roughly normally distributed with a mean of 85 and a standard deviation of 5 a. Between what values do we expect the grades of the middle 68% of the MAPEH students in performance 1 lie? b. Suppose you randomly select 16 MAPEH students, find the probability that the average grades of these students is at least 86. c. A MAPEH student whose grades lies in the upper 1% of the distribution (inclusive of the 1% cutoff) is considered extremely performing in Performance 1. Can you say that Jazzer, a randomly selected student who obtained a grade of 95, is one of those who performed extremely in Performance 1?

A randomly selected group of 560 students are assumed to have heights distributed normally with meanµ = 166 cm and standard deviation σ = 30 cm. Suppose a student is chosen randomly from this group. Finda. the probability that this student’s height is between 170 cm and 182 cm.b. the probability that this student’s height is bigger than 175 cm.

Suppose that you have a four-sided die that is equally weighted (i.e. equal chance of any of the four sides landing face up). The four values on the die are [12.5968, 2, -2 and -12.5968] . If we roll the die 81 times, record the average, and repeat this process a total of 100 times, what does the central limit theorem predict will be the standard deviation of the set of averages?   A. 1.00   B. 0.729   C. 0   D. 1.40

A distribution consists of three components with frequencies 45, 40 and 65, having the their mean 2, 2.5, and 2. Show that the mean of the combined distribution is 2.13 approximately.

Service time for a customer coming through a checkout counter in a retail store is a random variable with the mean of 1.0 minutes and standard deviation of 0.5 minutes. Suppose that the distribution of service time is fairly close to a normal distribution. Suppose there are two counters in a store, n = 11 customers in the first line and n2 = 30 customers in the second line. Find the probability that the difference between the mean service time for the shorter line X1 and the mean service time for the longer one X2 is more than 0.5 minutes. Assume that the service times for each customer can be regarded as independent random variables. Round your answer to two decimal places (e.g. 98.76). P = i

In a population of statistics students it was found that the mean score on the final is 150 with a standard deviation of 20 points. Ifa student is chosen at random, what is the probability that their grade will be less than 115? O 03867 O 0.3707 O 0.9599 O 0.5987 O 0.0401