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:
see the explanation
Step-by-step explanation:
we have
closed circle on 2 to closed circle on 6
That means -----> All real numbers greater than or equal to 2 and less than or equal to 6
In interval notation is ------> [2,6]
In set builder notation is ----> { x ∈ R | x ≥ 2 and x ≤ 6 }
In this question, the profit of the restaurant after t months is given by a polynomial function. To find when it begins to show a profit, we find the numerical values of the function for t, and it shows a profit when 
Profit after t months:
0 months:
This is P(0). So
1 month:
This is P(1). So
2 months:
This is P(2). So
3 months:
This is P(3). So
4 months:
This is P(4). So
5 months:
This is P(5). So
6 months:
This is P(6). So
7 months:
This is `P(7). So
After 7 months it shows profit, so it starts showing profit on the 6th month, and thus, the correct answer is given by option D.
For another example of a function involving numeric value, you can check brainly.com/question/24231879
Answer:
8.75:1
Step-by-step explanation:
i could be wrong but im pretty sure
