Answer:
-4.42
Step-by-step explanation:
Given the following :
Population mean (pm) = 8 hours
Sample mean (sm) = 6.9 hours
Number of observations (n) = 101 students
Sample standard deviation (sd) = 2.5
Using the t-statistic formula :
[(sm - pm) / (sd/√n)]
Hence,
[(6.9 - 8) / (2.5/√101)]
[(-1.1) / (2.5/10.05)]
-1.1 / 0.2487562
= −4.422
The test statistic = - 4.42 to the nearest hundredth.
Answer:
250 boys
Step-by-step explanation:
We know that the ratio is 9:10 from girls to boys
Take 225 and divide it by 9
225 ÷ 9 = 25
So we know that 25 is a factor of 225
We can the number of boys and multiply it by 25 to get 250
If we put it in the ratio form:
225:250 = 9/10
Check work:
25 x 9 = 225
25 x 10 = 250
last one. i can do the first part. put x = distance from top of ladder to the floor, y = distance from base of ladder to the wall (draw a picture) then pythagoras sez
<span><span>x2</span>+<span>y2</span>=25</span>
calculus says
<span>2x<span>x′</span>+2y<span>y′</span>=0</span>
and you are told that
<span><span>y′</span>=2</span>
so you know
<span>2x<span>x′</span>+4y=0</span>
or
<span><span>x′</span>=−<span><span>2y</span>x</span></span>
