ZIMS store sells its products on installments in Karachi. The store decided to investigate the link between the life of the product and the cost. The data collected from store is shown in Table 1.1: Table 1.1 LIFE OF PRODUCT (Years) COST (Thousand Rupees) 3.0 25 3.5 28 4.0 32 4.5 34 5.0 34 3.0 30 5.5 40 4.5 40 4.0 42 3.5 42 6.0 50 7.5 50 8.0 53 8.5 55 a) Plot a scatter chart from the above data. b) Find the equation of the least square regression line in the form y = a + bx. Given the value of a ??? b up to 3 decimal places. c) What are the exact interpretations of the estimated regression factors? d) Using your answer of part (b). Find the cost predicted by the regression line for 5 year’s life of a product.
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.
Question No. 1:
ZIMS store sells its products on installments in Karachi. The store decided to investigate the link between the life of the product and the cost. The data collected from store is shown in Table 1.1:
Table 1.1
LIFE OF PRODUCT (Years) COST (Thousand Rupees)
3.0 25
3.5 28
4.0 32
4.5 34
5.0 34
3.0 30
5.5 40
4.5 40
4.0 42
3.5 42
6.0 50
7.5 50
8.0 53
8.5 55
a) Plot a scatter chart from the above data.
b) Find the equation of the least square regression line in the form y = a + bx. Given the value of a ??? b up to 3 decimal places.
c) What are the exact interpretations of the estimated regression factors?
d) Using your answer of part (b). Find the cost predicted by the regression line for 5 year’s life of a product.
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