Question

The relationship between "strength" and "fineness" of cotton fibers was the subject of a study that produced the following data. (Give your answers correct to two decimal places.)

x, Strength	76	69	71	76	83	72	78	74	80	82
y, Fineness	4.3	4.5	4.7	4.0	4.1	4.2	5.0	4.9	4.3	4.3

(a) Draw a scatter diagram. (Do this on paper. Your instructor may ask you to turn in this work.)

(b) Find the 95% confidence interval for the mean measurement of fineness for fibers with a strength of 72.

Lower Limit
Upper Limit

(c) Find the 95% prediction interval for an individual measurement of fineness for fibers with a strength of 72.

Lower Limit
Upper Limit

Answer 1

The statistical software output for this problem is:

Hence,

b) 95% confidence interval:

Lower limit = 4.18

Upper limit = 4.86

c) 95% prediction interval:

Lower limit = 3.67

Upper limit = 5.37