Respuesta :
Answer:
Step-by-step explanation:
The confidence interval for the difference of two population means is expressed as
Confidence interval = (x1 - x2) ± z√(s²/n1 + s2²/n2)
Where
x1 = sample mean of low-tech industry
x2 = sample mean of consumer products industry
s1 = sample standard deviation low-tech industry
s2 = sample standard deviation for consumer products industry
n1 = number of samples of low-tech industry
n2 = number of samples of consumer products industry
a) x1 - x2 is the point estimate of the difference between the means of the two populations
Therefore,
Point estimate = 157 - 218 = - 61
b) the formula for standard error is expressed as
√(s1²/n1 + s2²/n2)
Variance = standard deviation²(s²)
s1² = 1563
s2² = 1602
Standard error = √(1563²/14 + 1602²/12) = 623.2
c) Degree of freedom =
(n1 - 1) + (n2 - 1) = (14 - 1) + (12 - 1) = 24
t-distribution with 24 degrees of freedom
According to the data given, we have that:
a) 61
b) 15.65
c) t-distribution with 24 degrees of freedom
Item a:
The point estimate is the difference between the two sample means, hence:
218 - 157 = 61.
Item b:
For each sample, the standard errors are:
[tex]s_l = \sqrt{\frac{1563}{14}} = 10.57[/tex]
[tex]s_h = \sqrt{\frac{1602}{12}} = 11.54[/tex]
For the difference of the two means, it is:
[tex]s = \sqrt{s_l^2 + s_h^2} = \sqrt{10.57^2 + 11.54^2} = 15.65[/tex]
Item c:
Samples of 14 and 12, hence 14 + 12 - 2 = 24 df.
A similar problem is given at https://brainly.com/question/12490448
