Answer:
a) 229 and 305 days
b) 229 days or less
c) 305 days or more
Step-by-step explanation:
The Empirical Rule(68-95-99.7 rule) states that, for a normally distributed random variable:
68% of the measures are within 1 standard deviation of the mean.
95% of the measures are within 2 standard deviation of the mean.
99.7% of the measures are within 3 standard deviations of the mean.
In this problem, we have that:
Mean = 267
Standard deviation = 19
(a) Between what values do the lengths of the middle 95% of all pregnancies fall?_____________and___________days
By the Empirical rule, 95% of all pregnancies fall within 2 standard deviations of the mean.
So
267 - 2*19 = 229 days
to
267 + 2*19 = 305 days
(b) How short are the shortest 2.5% of all pregnancies?______days or less
95% of all pregnancies fall within 2 standard deviations of the mean. The other 5% are more than 2 standard deviations from the mean. Since the distribution is symmetric, 2.5% is more than 2 standard deviations below the mean(shortest 2.5%) and 2.5% is more than 2 standard deviations above the mean(longest 2.5%). So
267 - 2*19 = 229 days
c) How long do the longest 2.5% of pregnancies last?________days or more
Explanation in b)
267 + 2*19 = 305 days
Answer:
Step-by-step explanation:
D is the answer
Answer:
Step-by-step explanation
Hello!
3x/4 + 6=42
3x/4=42-6 = 36
3x = 36*4
3x = 144
x= 144/3 =48
3/4 of 48 = (48*3) / 4 =36
36+6=42
the original number is 48
4x + 2y = 8 (1)
8x + 4y = -4y (2)
A) Two lines are parallel if they have the same gradient
- putting both equations into the gradient- intercept form ( y = mx + c where m is the gradient)
(1) 4x + 2y = 8
2y = 8 - 4x
y = -2x + 4
(2) 8x + 4y = -4y
<span> </span>8x = -4y - 4y
y =

y = -x
<span>
Thus the gradient of the two equations are different and as such the two lines are not parallel</span>
B) When two lines are perpendicular, the product of their gradient is -1

p = (-2) * (-1)
p = 2
<span> ∴
the two lines are not perpendicular either.</span>
Thus these lines are SKEWED LINES
Answer:
(l-3)(l+10)
Step-by-step explanation: