To solve for proportion we make use of the z statistic.
The procedure is to solve for the value of the z score and then locate for the
proportion using the standard distribution tables. The formula for z score is:
z = (X – μ) / σ
where X is the sample value, μ is the mean value and σ is
the standard deviation
when X = 70
z1 = (70 – 100) / 15 = -2
Using the standard distribution tables, proportion is P1
= 0.0228
when X = 130
z2 = (130 – 100) /15 = 2
Using the standard distribution tables, proportion is P2
= 0.9772
Therefore the proportion between X of 70 and 130 is:
P (70<X<130) = P2 – P1
P (70<X<130) = 0.9772 - 0.0228
P (70<X<130) = 0.9544
Therefore 0.9544 or 95.44% of the test takers scored
between 70 and 130.
Answer:
x=9
Step-by-step explanation:
We have two similar triangles because both lines are parallel, use proportions to solve:
Answer:
124 ft2
Step-by-step explanation:
The yard is a 12ft square so the length and width would both be 12ft. You multiply the length and width of the yard to get the area of the yard so 12x12=144. You have the length and width of the flower bed so 5x4=20. Once you have the area of both you can subtract the area the flower bed takes up of the lawn. 144-20=124 ft2.
Answer:
D. 9990 possible combinations
Step-by-step explanation:
The first digit has 10 choices (can be all of them), the second digit also has 10 choices. The third and fourth digits also have 10 choices.
Multiply them together you get 10*10*10*10 = 10000 possible combinations.
But since all 4 characters cannot be the same, we subtract 10 from 10000 (there are 10 combinations which the 4 characters are the same: 1111, 2222, 3333, 4444, 5555, 6666, 7777, 8888, 9999, and 0000) and we get 9990.
