1. A researcher found that the IQ scores of the ALS students in the Division of Quezon Province are no normally distributed with a mean of 110 and a standard deviation of 10. a. How many ALS students are needed to test so that the estimate will not be more than 5 from the population mean with a 99% level of confidence? b. Due to limited contact with ALS students, the researcher tested a small number of ALS students. Explain the effect of this small sample on the estimate of the parameter?
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.
II. Read the following problems carefully. Apply your skills in solving the following cases.
1. A researcher found that the IQ scores of the ALS students in the Division of Quezon Province are no
distributed
a. How many ALS students are needed to test so that the estimate will not be more than 5 from the
population mean with a 99% level of confidence?
b. Due to limited contact with ALS students, the researcher tested a small number of ALS students.
Explain the effect of this small sample on the estimate of the parameter?
2. A confidence
estimate is obtained is normal with a standard deviation of 9,
a. How many samples are considered in 98% confidence interval estimate for the mean?
b. What must be done to the
estimate? Support your answer.
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