need help on statistics please Assume that the length of pregnancies has a bell-
ID: 3044491 • Letter: N
Question
need help on statistics please
Assume that the length of pregnancies has a bell-shaped distribution with a mean of 270 days and a standard deviation of 15 days. Use the empirical rule to calculate the following. a. 2. About 68% of pregnancies last between About 95% of pregnancies last between About 99.7% of pregnancies last between and days. If a husband claims that his wife's child couldn't possibly be his because he was deployed 10 months ago, _days and_days b. and C. d. what might you tell him?Explanation / Answer
2)
a) as 68% of values fall with in 1 standard deviation from mean,
threfore about 68% of pregnancies last between 270-15 =255 and 270+15 =285 days
b)
as 95% of values fall with in 2 standard deviation from mean,
threfore about 95% of pregnancies last between 270-2*15 =240 and 270+2*15 =300 days
c)
as 99.7% of values fall with in 3 standard deviation from mean,
threfore about 99.7% of pregnancies last between 270-3*15 =225 and 270+3*15 =315 days
d)
as 10 months (300 days ) is 2 standard deviation away and 2.5% birth days fall beyond that also ; therefore there is a possibility that the child will be his and he might go for a DNA check in case of doubt.
4)
here z score is a measure of relative performance in the group
z score =(X-mean)/std deviation
Rachel z score =(50000-35000)/8000 =1.875
Rob's Z score =(50000-60000)/5000=-2
as z score for Rachel is higher therefore she is earning more money in her own distribution with respect to Rob,.
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