The SAT scores of 20 randomly selected high school students has
a mean of =1,185 and...
The SAT scores of 20 randomly selected high school students has
a mean of =1,185 and a sample standard deviation s=168.0. Construct
an 98% confidence interval for the true population mean and
interpret this interval
Solutions
Expert Solution
Solution :
Given that,
= 1,185
s = 168.0
n = 20
Degrees of freedom = df = n - 1 = 20 - 1 = 19
At 90% confidence level the z is ,
= 1 - 90% = 1 - 0.90 = 0.10
/ 2 = 0.10 / 2 = 0.05
t
/2,df = t0.05,19 = .2.093
Margin of error = E = t/2,df
* (s /n)
= 2.093 * (168.0 /
20 )
= 78.62
Margin of error = 78.62
The 90% confidence interval estimate of the population mean
is,
The SAT scores of 20 randomly selected high school students has
a mean of =1,185 and a sample standard deviation s=168.0. Construct
an 98% confidence interval for the true population mean and
interpret this interval
10)
The SAT scores for 12 randomly selected seniors at a particular
high school are given below. Assume that the SAT scores for seniors
at this high school are normally distributed.
1,271
1,288
1,278
616
1,072
944
1,048
968
931
990
891
849
a) Find a 95% confidence interval for the true mean SAT score
for students at this high school.
b) Provide the right endpoint of the interval
as your answer.
Round your answer to the nearest whole
number.
The SAT scores for US high school students are normally
distributed with a mean of 1500 and a standard deviation of
100.
1. Calculate the probability that a randomly selected student
has a SAT score greater than 1650.
2. Calculate the probability that a randomly selected student
has a SAT score between 1400 and 1650, inclusive.
3. If we have random sample of 100 students, find the probability
that the mean scores between 1485 and 1510, inclusive.
Q3.(15) The SAT scores for US high school students are normally
distributed with a mean of 1500 and a standard deviation of
100.
1.(5) Calculate the probability that a randomly selected student
has a SAT score greater than 1650.
2.(5) Calculate the probability that a randomly selected student
has a SAT score between 1400 and 1650, inclusive.
3.(5) If we have random sample of 100 students, find the
probability that the mean scores between 1485 and 1510,
inclusive.
The combined SAT scores for the students at a local high school
are normally distributed with a mean of 1521 and a standard
deviation of 298. The local college includes a minimum score of
1044 in its admission requirements. What percentage of students
from this school earn scores that fail to satisfy the admission
requirement?
The combined SAT scores for the students at a local high school
are normally distributed with a mean of 1488 and a standard
deviation of 292. The local college includes a minimum score of
2014 in its admission requirements. What percentage of students
from this school earn scores that fail to satisfy the admission
requirement? P(X < 2014) =________ % Enter your answer as a
percent accurate to 1 decimal place (do not enter the "%" sign).
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