Answer:

Step-by-step explanation:













Sum of fractions 
Answer: About 99.7% IQ scores falls within 43 and 157.
Step-by-step explanation:
According to the empirical rule , if a data follows normal distribution then about 99.7% of the population lies with in three standard deviations from mean.
Given: IQ test have a bell-shaped distribution with a mean of 100 and a standard deviation of 19.
Since , the graph of normal distribution is bell-shaped , it mean that IQ scores follow normal distribution.
Then, About 99.7% IQ scores falls within Mean ± 3 (Standard deviation).
i.e. About 99.7% IQ scores falls within 100± 3(19).
i.e. About 99.7% IQ scores falls within 100- 57 and 100+57.
i.e. About 99.7% IQ scores falls within 43 and 157.
Therefore , by empirical rule
About 99.7% IQ scores falls within 43 and 157.
Answer:
Step-by-step explanation:
Let X be the length of pregnancy.
X is N(268, 15)
a) Prob of pregnancy lasting 307 days or longer
= P(X>307) = 
=0.5-0.4953
=0.0047
b) Lowest 2% is 2nd percentile
Z=-2.55
X score = 268-2.55(15)
= 229.75 days
If length of days >230 days then it is not premature.
Answer:
I can't help u with this cause I do not know this kind of math I only learn about Fractions and other math except for algebra.
Step-by-step explanation:
I wish u the best of luck on trying to figure out this answer.