Answer:
Restudy and try to take it again.
Step-by-step explanation:
Try watching math videos and do extra studying on the areas you missed on your last attempt.
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:
Distance =√(x₁ - y₁)²+ (x₂ - y₂)² = √97 = 9.85
Step-by-step explanation:
The Matrix X and Y could also be referred to as vectors in Rⁿ dimensions.
if Vector X = ( x₁ , x₂) and Vector Y = (y₁ , y₂)
then, Distance (X-Y) = ||X-Y|| = √(x₁ - y₁)²+ (x₂ - y₂)²
where, x₁ = 8, x₂ = -5 and y₁ = -1 , y₂ = -9
Distance = √(8 - (-1))²+ (-5 - (-9))² = √9² + 4² =√97 = 9.85
Answer: 3x-5y=-9 is simplified to y=3/5x+9/5
x+2y=8 is simplified to y=-1/2x+4
