Answer:
The probability is 0.9909.
Step-by-step explanation:
Test statistic (z) = (sample mean - population mean) ÷ (sd/√n)
sample mean = 290 days
population mean = 298 days
sd = 22 days
n = 42
z = (290 - 298) ÷ (22/√42) = -8 ÷ 3.395 = -2.36
The cumulative area of the test statistic is the probability that the mean gestation period is less than 290 days. The cumulative area is 0.9909. Therefore the probability is 0.9909.
Answer:
The area (probability) is: 0.6864.
Step-by-step explanation:
According to the statement, we are in front of a normal distribution with the following parameters:
µ (mean) = 0
σ (Standard deviation) = 1.
Then we need to find the area of the shaded region, which is the area between the points -1.21 < z < 0.84.
And the area (probability) is: 0.6864.
Answer:
Option D is correct.
13x = 39
Step-by-step explanation:
The system of equation is given:
....[1]
.....[2]
Multiply equation [1] by 5 to both sides we have;
.....[3]
Using elimination method:
Add [2] and [3] equations to eliminate y and solve for x, we have;

Divide both sides by 13 we get;
x = 3
Substitute x in [1] we have;
2(3)-y = -4
6-y = -4
Subtract 6 from both sides we have;
-y = -10
Divide both sides by -1 we have;
y = 10
⇒Solution: (3, 10)
Therefore, an equation can replace 3x+5y = 59 in the original system and still produce the same solution is,
13x = 39