Answer:
21
Step-by-step explanation:
Using<em> Simple Random Sampling</em>, we can estimate the sample size by the formula
where
n = sample size
Z = the z-score corresponding to the confidence level 99.5%
S = the assumed standard deviation = 3 seconds
e = margin of error = 2 seconds
<em>It is worth noticing that the higher the confidence level, the larger the sample should be.
</em>
The z-score corresponding to a confidence level of 99.5% can be obtained either with a table or the computer and equals
Z = 3.023
Replacing the values in our formula
So the size of the sample should be at least 21.
A. the lower extreme is an outer but the upper exterme is not
Answer:
a) x = -270
b) y = 304/9 or y = 33.78
c) x = -37.8
Step-by-step explanation:
y varies directly with x so y = kx
a)
y = kx
k = y/x
k = 10/-30 = -1/3
So
y = -1/3 x
If y = 90 then
90 = -1/3 x
x = 90 *(-3) = -270
b)
k = y/x
k = -19/-4.5
k = 38/9
So
y = 38/9 x
If x = - 8 then
y = 38/9 *(-8)
y = 304/9 or y = 33.78
c)
k = y/x
k = -4.3 / 12.9
k = - 1/3
So
y = -1/3 x
If y = 12.6 then
12.6 = -1/3 x
x = 12.6 *(-3)
x = -37.8
Answer:
c
Step-by-step explanation:
Answer:
Right answer is B) x>-10 and x<10