Use the graph to answer the question.
1 answer:
You might be interested in
Answer:
x=0.450765 or x=−0.950765
Step-by-step explanation:
14x² + 7x - 6
→ Find the product, sum and factors
Product = -6
Sum = 7
Factors = No factors
→ Since there are no factors utilise the quadratic formula
→ List the values of a, b and c
a = 14
b = 7
c= -6
→ Substitute into the formula
→ Simplify
x=0.450765 or x=−0.950765
Answer:
Critical value: z = 1.28
The 80% confidence interval for the mean repair cost for the washers is between $46.487 and $82.033.
Step-by-step explanation:
We have that to find our level, that is the subtraction of 1 by the confidence interval divided by 2. So:
Now, we have to find z in the Ztable as such z has a pvalue of
So it is z with a pvalue of 1-0.1 = 0.9, so z = 1.28
Now, find the margin of error M as such
In which is the standard deviation of the population and n is the size of the sample.
So
The lower end of the interval is the mean subtracted by M. So 64.26 - 17.773 = $46.487.
The upper end of the interval is M added to the mean. So 64.26 + 17.773 = $82.033.
The 80% confidence interval for the mean repair cost for the washers is between $46.487 and $82.033.