Question

1. A sample size of 49 drawn from a population with a mean of 36 and a standard deviation of 15 for the size of an English class. What is the probability the class will have greater than 40

a. .9693

b. .4693

c. .0808

d. .0307

2. A sample size of 49 drawn from a population with a mean of 36 and a standard deviation of 15 for the size of an English class. What is the probability the class will was between 30 and 40?

a. .0363

b. .4693

c. .9667

d. .1608

3. The expected value (the average of all possible samples of a gin size) of the sample mean is expected to be equal to the mean of the population from which the random samples are taken.

a. true

b. false

Answer #1

Solution :

Given that,

mean = = 36

standard deviation = = 15

n = 49

= = 36

= / n = 15 / 49 = 2.14

1) P( > 40) = 1 - P( < 40)

= 1 - P[( - ) / < (40 - 36) /2.14 ]

= 1 - P(z < 1.87)

Using z table,

= 1 - 0.9693

= 0.0307

2) P(30 < < 40)

= P[(30 - 36) / 2.14 < ( - ) / < (40 - 36) / 2.14 )]

= P(-2.80 < Z < 1.87)

= P(Z < 1.87) - P(Z < -2.80)

Using z table,

= 0.9693 - 0.0026

= 0.9667

3) True

A random sample of size 36 is taken from a population with mean
µ = 17 and standard deviation σ = 4. The probability that the
sample mean is greater than 18 is ________.
a. 0.8413
b. 0.0668
c. 0.1587
d. 0.9332

A sample of size 36 cases is drawn from a negatively skewed
population with mean of 2 and standard deviation of 3. what is the
probability that the sample mean obtained will be negative? How
many points must we go from the mean to include 50 percent of all
sample means.

1. A sample size of 80 will be drawn from a population
with mean 20 and standard deviation 15. Find the probability that
x̄ will be between 18 and 21.
A) 0.6087 B) 0.5841 C) 0.1170 D) 0.2743
2. A certain car model has a mean gas mileage of 29
miles per gallon (mpg) with a standard deviation 5 mpg. A pizza
delivery company buys 47 of these cars. What is the probability
that the average mileage of the fleet...

A sample of size 15will be drawn from a population with mean 135
and standard deviation 36
.
(a) Is it appropriate to use the normal distribution to find
probabilities for x?
(b) If appropriate find the probability that X will be
less than 118
.
(c) If appropriate find the
90th percentile of x
A sample of size 15will be drawn from a population with mean 135
and standard deviation 36
.
(a) Is it appropriate to use the normal...

A random sample of n=36 observations is drawn from a population
with a mean equal to 60 and a standard deviation equal to 36.
a. Find the probability that x? is less than 48 ____
b. Find the probability that x? is greater than 63____
c. Find the probability that x? falls between 48 and 78 ____

1.
Suppose that a random sample of size 36 is to be selected from a
population with mean 49 and standard deviation 9. What is the
approximate probability that will be within 0.5 of the
population mean?
a.
0.5222
b.
0.0443
c.
0.2611
d.
0.4611
e.
0.7389
2.
Suppose that x is normally distributed with a mean of 60 and a
standard deviation of 9. What is P(x 68.73)?
a.
0.834
b.
0.166
c.
0.157
d.
0.334
e.
0.170

Suppose samples of size 100 are drawn randomly from a population
that has a mean of 20 and a standard deviation of 5. What is the
probability of observing a sample mean equal to or greater than
20.5?
0.1587
0.4192
0.9192
0.1634
0.8384

a simple random sample of size 36 is taken from a normal
population with mean 20 and standard deivation of 15. What is the
probability the sample,neab,xbar based on these 36 observations
will be within 4 units of the population mean. round to the
hundreths placee

a simple random sample of size 36 is taken from a normal
population with mean 20 and standard deivation of 15. What is the
probability the sample,neab,xbar based on these 36 observations
will be within 4 units of the population mean. round to the
hundreths place

A random sample of size 49 is taken from a population with mean
µ = 26 and standard deviation σ = 7. Use an appropriate normal
transformation to calculate the probability that the sample mean is
between 24 and 27.
Group of answer choices
0.0228
0.8641
0.8413
0.8185

ADVERTISEMENT

Get Answers For Free

Most questions answered within 1 hours.

ADVERTISEMENT

asked 6 minutes ago

asked 14 minutes ago

asked 34 minutes ago

asked 38 minutes ago

asked 44 minutes ago

asked 45 minutes ago

asked 1 hour ago

asked 1 hour ago

asked 2 hours ago

asked 2 hours ago

asked 3 hours ago

asked 3 hours ago