Answer:
A) 68.33%
B) (234, 298)
Step-by-step explanation:
We have that the mean is 266 days (m) and the standard deviation is 16 days (sd), so we are asked:
A. P (250 x < 282)
P ((x1 - m) / sd < x < (x2 - m) / sd)
P ((250 - 266) / 16 < x < (282 - 266) / 16)
P (- 1 < z < 1)
P (z < 1) - P (-1 < z)
If we look in the normal distribution table we have to:
P (-1 < z) = 0.1587
P (z < 1) = 0.8413
replacing
0.8413 - 0.1587 = 0.6833
The percentage of pregnancies last between 250 and 282 days is 68.33%
B. We apply the experimental formula of 68-95-99.7
For middle 95% it is:
(m - 2 * sd, m + 2 * sd)
Thus,
m - 2 * sd <x <m + 2 * sd
we replace
266 - 2 * 16 <x <266 + 2 * 16
234 <x <298
That is, the interval would be (234, 298)
In an hour, 80 people could ride the ferris wheel. So, that means in 3 hours 240 people could ride it.
8,500,000
Round the number 4 to 5 because the number 7 is behind it.
Answer:
<em>The second choice is correct. It can be factored as:</em>
Step-by-step explanation:
<u>The Difference of Squares Method for Factoring</u>
The expression:
Is a widely used method to factor binomials that are expressed as the subtraction of two perfect squares.
The condition for a binomial to be factored by using this method is that both terms must have an exact square root and they must be subtracted.
The last two choices are not valid because they are not a subtraction but an addition.
The first choice is not valid because none of the terms is a perfect square.
The second choice is correct. It can be factored as:
The answer is f because it equals 1/3 and f is 1/3
