Statistics
posted by Bill .
Use this information to calculate the mean and standard deviation of this random variable.
P(x) .25, .05, .55, .15

Find the mean first = sum of scores/number of scores
Subtract each of the scores from the mean and square each difference. Find the sum of these squares. Divide that by the number of scores to get variance.
Standard deviation = square root of variance
I'll let you do the calculations.
Respond to this Question
Similar Questions

Statistics
1) A Motor Company has purchased steel parts from a supplier for several years and has found that 10% of the parts must be returned because they are defective. An order of 25 parts is received. What are the mean and standard deviation … 
math
Suppose x is a random variable with mean and standard deviation. If a large number of trials is observed, at least what percentage of these values is expected to lie beween mean2(standard deviation) and mean + 2(standard deviation) … 
STATISTICS
Consider a binomial random variable where the number of trials is 12 and the probability of success on each trial is 0.25. Find the mean and standard deviation of this random variable. I have a mean of 4 and a standard deviation of … 
Math
Random variables X and Y are both normally distributed with mean 100 and standard deviation 4. It is known that random variable X+Y is also a normal distribution. a. What is the mean of X+Y? 
Statistics
Given that x is a normally distributed random variable with a mean of 28 and a standard deviation of 7, find the following probability: P(x<28) I understand that the means is 28 and the standard deviation is 7. However what I don't … 
Statistics
I am so lost on this statistics question would someone help me figure out how to answer it? 
statistics
A specific study found that the average number of doctor visits per year for people over 55 is 8 with a standard deviation of 2. Assume that the variable is normally distributed. 1. Identify the population mean. The population mean … 
Statistics
According to a study by the Centers for Disease Control, the national mean hospital stay after childbirth is 2.1 days. Reviewing records at her own hospital, a hospital administrator calculates that the mean hospital stay for a random … 
Stats
The random variable U has mean 10 and standard deviation 5.The random variable V is de ned by V =12(U + 5).Find the mean and standard deviation of V. 
statistics
population has mean 53 and standard deviation 12. Calculate the standard deviation of x bar for a random sample of size 12.