Suppose that the average number of Facebook friends users have is normally distributed with a mean of 138 and a standard deviation of about 57. Assume forty-two individuals are randomly chosen. Answer the following questions. Round all answers to 4 decimal places where possible. What is the distribution of ¯xx¯? ¯xx¯ ~ N(Correct,Correct) For the group of 42, find the probability that the average number of friends is less than 134. Find the first quartile for the average number of Facebook friends. For part b), is the assumption that the distribution is normal necessary? NoYes only need 2 and 3
Inverse Normal Distribution
The method used for finding the corresponding z-critical value in a normal distribution using the known probability is said to be an inverse normal distribution. The inverse normal distribution is a continuous probability distribution with a family of two parameters.
Mean, Median, Mode
It is a descriptive summary of a data set. It can be defined by using some of the measures. The central tendencies do not provide information regarding individual data from the dataset. However, they give a summary of the data set. The central tendency or measure of central tendency is a central or typical value for a probability distribution.
Z-Scores
A z-score is a unit of measurement used in statistics to describe the position of a raw score in terms of its distance from the mean, measured with reference to standard deviation from the mean. Z-scores are useful in statistics because they allow comparison between two scores that belong to different normal distributions.
Suppose that the average number of Facebook friends users have is
- What is the distribution of ¯xx¯? ¯xx¯ ~ N(Correct,Correct)
- For the group of 42, find the
probability that the average number of friends is less than 134. - Find the first
quartile for the average number of Facebook friends. - For part b), is the assumption that the distribution is normal necessary? NoYes
only need 2 and 3
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