Answer:
Mean = 78.2
Standard deviation = 5.8
Step-by-step explanation:
Mathematically z-score;
= (x-mean)/SD
From the question;
12% of test scores were above 85
Thus;
P( x > 85) = 12%
P(x > 85) = 0.12
Now let’s get the z-score that has a probability of 0.12
This can be obtained from the standard normal distribution table and it is = 1.175
Thus;
1.175 = (85 - mean)/SD
let’s call the mean a and the SD b
1.175 = (85-a)/b
1.175b = 85 - a
a = 85 - 1.175b ••••••••(i)
Secondly 8% of scores were below 70
Let’s find the z-score corresponding to this proportion;
We use the standard normal distribution table as usual;
P( x < 70) = 0.08
z-score = -1.405
Thus;
-1.405 =( 70-a)/b
-1.405b = 70-a
a = 70 + 1.405b ••••••(ii)
Equate the two a
70 + 1.405b = 85 - 1.175b
85 -70 = 1.405b + 1.175b
15 = 2.58b
b = 15/2.58
b = 5.81
a = 70 + 1.405b
a = 70 + 1.405(5.81)
a = 78.16
So mean = 78.2 and Standard deviation is 5.8
Answer:
ok
Step-by-step explanation:
An agreeement made by the Pilgrims to govern themselves.
Agreement made by pilgrims to govern themselves.
Answer:
A haircut costs $31
Coloring hair costs $93
Step-by-step explanation:
h = haircut
c = color
First equation: 1h + 2c = 217
Second equation: 2h + 1c = 155
Solve using elimination:
First, multiply both the equations so that they cancel the h's out:
First equation:
-1(2h + 1c = 155)
-2h - 1c = -155
Second equation:
2(1h + 2c = 217)
2h + 4c = 434
Then, put the equations together, and solve:
2h + 4c = 434
-2h - 1c = -155
3c = 279
c = 93
Find h:
2h + 1c = 155
2h + 1(93) = 155
2h + 93 = 155
2h = 62
h = 31
Hope this helped!
Answer:
Mr. Martin's statement is correct.
Step-by-step explanation:
First we select a value of q that is less than 6:
q = 3
Then we <u>write the equation:</u>
And <u>solve for x</u>:
The solution is positive because x > 0.
--
Then we select a value of q that is not less than 6:
q = 9
Then we <u>write the equation:</u>
And <u>solve for x</u>:
The solution is negative because x > 0.
Answer:
$13
Step-by-step explanation:
multiply 65 by 80 then divide by 100, you get 52, so subtract 65 from 52 you get 13
