Answer:
Step-by-step explanation:
Hello!
The mean is a measurement of central tendency that shows what is the most expected value of the variable. The standard deviation is a measurement of variability, it shows you how distant or dispersed are the values of a certain population or sample in regards to the value of the mean.
In this example the variable is X: score obtained on a math test.
It's mean is μ= 52 and its standard deviation is σ= 10
To know how many standard deviations away is a value of X concerning the mean you have to first subtract the mean to the value of X, X - μ, and then you have to divide it by σ:
(X - μ)/ σ
If X=76
(76 - 52)/ 10= 2.4
The score obtained by Andrea is 2.4σ away from the mean.
I hope it helps!
Answer:
y= 5x +12
Step-by-step explanation:
y=mx+b is slope intercept form
m = slope
b = y intercept
Answer:
(130.08, 139.92)
Step-by-step explanation:
Given that:
Mean (m) = 135
Standard deviation (σ) = 30
Sample size (n) = 100
α = 90%
The confidence interval value is obtained using the relation:
Mean ± Zcritical * (standard deviation / sqrt(n))
Zcritical at 90% = 1.64
standard deviation / sqrt(n) = 30 / sqrt(100)
= 30 / 10 = 3
Hence,
135 ± 1.64 * (3)
Lower limit : 135 - (1.64 * 3) = 130.08
Upper limit : 135 + (1.64 * 3) = 139.92
Hence,
Confidence interval = (130.08, 139.92)
You have to subtract 6y from both sides or subtract 7y from both sides(if you wanted to have a negative).
