AZ-score describes the position of a raw score in terms of its distance from the mean, when measured in standard deviation units. The z-score is positive if the value lies above the mean, and negative if it lies below the mean. It is also known as a standard score, because it allows comparison of scores on different kinds of variables by standardizing the distribution. To further understand the application of z- score for any normally distributed data, answer the following problems. 1. Rodrigo earned a score of 940 on a national achievement test. The mean test score was 850 with a standard deviation of 100. What proportion of students had a higher score than Rodrigo? (Assume that test scores are normally distributed.) If there were 100,000 students who took the test, how many would be expected to have a higher score than Rodrigo? 2. The following letter appeared in the popular "Dear Abby" newspaper advice column in the 1970s: Dear Abby. You wrote in your column that a woman is pregnant for 266 days. Who said so? I carried my baby for ten months and five days, and there is no doubt about it because I know the exact date my baby was conceived. My husband is in the Navy and it couldn't have possibly been conceived any other time because I saw him only once for an hour, and I didn't see him again until the day before the baby was bon. 203 I don't drink or run around, and there is no way this baby isn't his, so please print a retraction about the 266-day carrying time because otherwise I am in a lot of trouble. - San Diego Reader The advice column was founded in 1956 by Pauline Phillips under the pen name "Abigail Van Buren" and carried on up to today by her daughter, Jeanne Philips, who now owns the legal rights to the pseudonym. Suppose that according tend to be normally distributed with m= 266 days and s= 16 days. Perform a probability calculation that addresses San Diego Reader's credibility, presuming she was pregnant for 308 days. What would you conclude and why? pediatricians, pregnancy durations, let's call them x, 3. Why are z - scores important? 4. How do you interpret a z- score? 5. How to calculate a raw score when a z- score is known?
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.
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