This can be solved using the formula for t test which is = x - mu over standard deviation divided by the square root of the number of samples. In this case, it is 1185 - 1200 over 70 divided by square root of 100 which give us a value of 2.14 which is equal to .9839 in area. Only rarely, just over one time in a hundred tries of 100 light bulbs, would the average life exceed 1200 hours.
5m-8=3m+8
(Plus the '8' to both sides)
5m=3m+16
(Subtract '3m' from both sides)
2m=16
(Divide by 2)
m=8
I'm sure you know how to find the slope of a line if you know 2 points
on it ... The slope is ...
(difference in y-values) / (difference in x-values) .
Right ?
OK. Each line in these tables is a point on the graph of the table.
Pick two points from the table, and you can get the slope of the line
from them.
The first table (Plan-A) has these points in it:
1 . . . . . $20.15
2 . . . . . $20.30
3 . . . . . $20.45
4 . . . . . $20.60
You want to find the equation of the line with these 4 points on it.
That means you need to find the slope and the intercept of the line.
Take any two points straight from the table. I'll use the first two:
1 . . . . . $20.15
2 . . . . . $20.30
There you have two points on the line: (1, 20.15) and (2, 20.30) .
The slope is (difference in 'y') / (difference in 'x').
Difference in 'y' = (20.30 - 20.15) = 0.15
Difference in 'x' = (2 - 1) = 1
Slope of the line = (0.15) / 1 = <u>0.15</u>
(What that really means is 15 cents per minute on Plan-A.)
Now you know that the equation of the line is [ <u>y = 0.15x + intercept</u> ].
Can you think of a way to find the intercept ?
Remember ... every point in the table is on the line.
So why not just take one of these points in the table, put it into the part of the equation that you already have, and watch the intercept fall out ?
You could use any point at all from the table.
I'll use the 3rd one.
<u>y = 0.15x + intercept</u>
20.45 = 0.15(3) + intercept
20.45 = 0.45 + intercept
Subtract 0.45 from each side: <u>20.00 = intercept</u>
The equation of the graph for Plan-A is <em>Charge = 0.15(minutes) + $20.00</em>
===============================
Plan-B:
First two points:
Difference in y-values = (8.00 - 6.50) = 1.50
Difference in x-values = (10 - 5) = 5
Slope of the line = (1.50) / (5) = .30 (30 cents per minute)
Intercept = 5.00
Charge = 0.3(minutes) + $5.00
======================================
Plan-C:
Slope = 4.50 / 10 = 0.45
Intercept = zero
=================================
Plan-D:
Slope = (16.50 - 11.00) / (30 - 20) = 5.5/10 = 0.55
Intercept = zero
In each plan, the intercept is the cost just to sign up, before you use
the phone, and then the slope is the cost for each minute of talking on it.
Answer:
1) n = 3.5
2) x = 4
Step-by-step explanation:
4 + 3 = 7 divide by 5 = 7/2
8 gallons = 128 cups
20 guests x 2 cups= 40 cups of punch estimated
128 cups-40 cups = <span>88 cups left over.</span>