Answer:
B
Step-by-step explanation:
cause when we substitute 5 in the equation we get 3<7which is true.
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:
<em>The area of a circle is πr2 and the perimeter (circumference) is 2πr</em>
<em>thank</em><em> </em><em>you</em><em> </em><em />
<em>312 ft²</em>
- Step-by-step explanation:
<em>3 rectangles
</em>
<em>2 triangles</em>
<em>4 yd = 12 ft</em>
<em>A = 4ft×12ft + 8ft×12ft + 10ft×12ft + 2×6ft×8ft/2</em>
<em>= 48ft² + 96ft² + 120ft² + 48ft²</em>
<em>= 312 ft²</em>
Answer:
6²= 6×6= 36
√81= 9
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