The mean ( average ) is given as 1200 hours.
The standard deviation is 200, sample size is 100.
Find the standard error:
√(200^2 / 100) = 20
Now calculate the confidence interval. For 95% the Z number is 1.96
Multiply Z by the standard error:
1.96 x 20 =39.2
Now find the range that the mean should be within:
1200 - 39.2 = 1160.8
1200 + 39.2 = 1239.2
The samples should be between 1160.8 and 1239.2 for a 95% confidence interval.
Since the average was 1050, which is below 1160.8 the bulbs are not in compliance.
Answer:
x = 3
Step-by-step explanation:
2(4-3x) + 5(2x-3) = 20-5x
8 - 6x + 10x - 15 = 20 - 5x
-6x + 10x + 5x = 20 - 8 + 15
9x = 27
x = 3
Number of matchsticks required is 2. Rule which matchstick pattern is 2 x n.
For the last on you need to set up a proportion with the degrees. You know the arcs add to 360 and that small section is 120 so you set it equal to x over the entire area. X is the answer. The formulas are next to all answers
This is an arithmetic sequence with first term (a) = 11, number of terms (n) = 57, sum of nth term (Sn) = 19,779.
Let the amount of money she saved more each month be d, then
Sn = n/2(2a + (n - 1)d)
19,779 = 57/2(2(11) + (57 - 1)d)
19,779 = 28.5(22 + 56d)
19,779 = 627 + 1,596d
19,779 - 627 = 1,596d
d = 19,152/1,596 = 12
Therefore, she saved $12.00 more each month.
