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
Solution:
A coin is flipped three times,resulting three heads in a row.
Since Steve has mentioned that , each flip of a coin is unconnected to the previous flip.
Two or more events are said to be independent if occurrence of one of them is not affected by the Occurrence of other.
This is an example of independent events.
In terms of probability, P (A∩B∩C)= P(A)×P(B)×P(C)
The difference between 2x+16=14 than 2x+16=x+14 is that you would have to solve x in two different ways like finding the first equation another way than to the second equation ( I think ).
Your answer is A.) for ur problem
Step-by-step explanation:
<u>Given functions:</u>
<u>Find (f*g)(6):</u>
- (f*g)(6) = f(6)*g(6) = 6(6 - 1)*3(6) = 30*18 = 540
<u>In case it is a composite function (f · g)(6) the answer is different:</u>
- (f · g)(6) = f(g(6)) = f(3*6) = f(18) = 18*(18 - 1) = 306
