D) as age increases, weight increases by 5
Hi there!
Let's start by replacing "a number" by the letter "x" so that we can do an equation and isolate "x" to find your answer :
(x -
) +
= -7
subtract
on each side of the equation
x -
= -8.25
add
on each side of the equation
x = -7.5
-7.5 - 3/4 = -8.25
-8.25 + 5/4 = <u>-7</u>
So your answer is : Three-fourths was subtracted from -7.5, and then 5/4 was added to the result. The sum was -7.
There you go! I really hope this helped, if there's anything just let me know! :)
Answer:
a) 16%
b) 2.5%
Step-by-step explanation:
a)
The mean is 70 with standard deviation(SD) of 3 and you are asked to find out the percentage of staff that have <67(70-3 inch= mean - 1 SD) inch size, which means 1 SD below the mean (<-1 SD). Using 68-95-99.7 rule, you can know that 68% of the population is inside 1 SD range from the mean ( -1 SD to + 1 SD).
To put it on another perspective, there are 32% of the population that have < -1 SD and > +1 SD value. Assuming the distribution is symmetrical, then the value of < - 1 SD alone is 32%/2= 16%
b)
The question asks how many populations have size >76 inches, or mean + 2 SD (70+3*2 inch).
You can also solve this using 68-95-99.7 rule, but you take 95% value as the question asking for 2 SD instead. Since 95% of population is inside 2 SD range from the mean ( -2 SD to + 2 SD), so there are 5% of population that have < -2 SD and > +2 SD value. Assuming the distribution is symmetrical, then the value of > +2 SD alone is 5%/2= 2.5%