BUAL 2650 Exam 1 Homework Questions || Answered
with Absolute Accuracy.
The z value tells us the number of _______ that a value of x is from the mean correct answers
standard deviation
The grade a student received on an examination was transformed to a z value, which was
negative. Therefore, we know that he scored correct answers below the mean
If the p-value for testing H0 versus Ha is 0.0174 we will correct answers Since p-value = .0174 <
.05, we will reject the null hypothesis in favor of the alternative when α = .10 and .05. However,
we will fail to reject the null hypothesis when α = .01 and .001 since p-value = .0174 > .01.
if the sample mean is 1,241.2, sample standard deviation is s= 110.8 and the p-value testing H0
against Ha is 0.0174
Describe how much evidence we have that the new button's mean lifetime exceeds the mean
lifetime of the best remote button currently on the market correct answers With a p-value
of .0174, we conclude there is strong evidence that the mean lifetime of the new remote control
button is greater than 1200 hours.
Values of the standard normal random variable are measured: correct answers in the number of
standard deviations from the mean
This number is given by the z-table
The p-value for testing H0 versus Ha can be calculated to be 0.005,, Determine whether H0
would be rejected at each a= .10, .05, .01, and .001 correct answers A calculated p-value of 0.005
< 0.01, so we will reject the null hypothesis in favor of the alternative when α = 0.10, 0.05 and
0.01. However, we will fail to reject the null hypothesis when α = 0.001 since p-value = 0.005 >
0.001.
Consider a normal population with a mean of 10 and a variance of 4. find P (X>7) correct
answers z = (7 − 10)/√4 = −1.5
P(X > 7) = 1 − .0668 = .9332
Why do we need the z-score correct answers tells us how many standard deviations the value
falls from above or below the mean
-positive z-score: value x is ABOVE the mean
-negative z-score: value X is BELOW the mean
z-score table and formula correct answers z=(raw score-mean)/standard deviation
Confidence level correct answers the probability that the interval estimate will contain the
population parameter
, -DOES NOT MEAN probability that parameter will happen
The specific shape of each normal distribution is determined by its ______ and _______ correct
answers mean and standard deviation
-larger standard deviations make for longer curves while smaller standard deviations make for
taller curves.
Consider a normal population with a mean of 10 and a variance of 4. find P(X<6) correct
answers z = (6 − 10)/√4 = −2
P(X < 6) = .0228
______ values of the standards deviation result in a normal curve that is wider and flatter correct
answers larger
-The values are more spread out and further from the mean
The number of standard deviations that a value, x, is from the mean is a(an) _______ correct
answers z score
What is the probability that a standard normal random variable will be between .3 and 3.2 correct
answers P(.3 ≤ z ≤ 3.2) = .9993 − .6179 = .3814
Consider a normal population with a mean of 10 and a variance of 4. Find P(x≥10) correct
answers z = 0
P(z ≥ 0) = .5
An aptitude test has a mean score of 80 and a standard deviation of 5. The population of scores is
normally distributed. What proportion of tests has scores over 90? correct answers z=(90 − 80)/5
=2
p(X > 90) = 1 − .9772 = .0228
________ values of the standard deviation result in a normal curve that is narrower and more
peaked correct answers smaller
-the values are highly concentrated around the mean
What is the probability that a standard normal random variable will be between -2 and 2? correct
answers P(−2 ≤ z ≤ +2) = .9772 − .0228 = .9544
Properties of the normal probability distribution correct answers -The normal distribution is
symmetric
-The mean, median and mode are equal
-The area under the normal curve to the right of the mean is equal to the area under the normal
curve to the left of the mean.
-99.7% of all possible observed values of the random variable x are within plus or minus three
standard deviations of the population mean.
with Absolute Accuracy.
The z value tells us the number of _______ that a value of x is from the mean correct answers
standard deviation
The grade a student received on an examination was transformed to a z value, which was
negative. Therefore, we know that he scored correct answers below the mean
If the p-value for testing H0 versus Ha is 0.0174 we will correct answers Since p-value = .0174 <
.05, we will reject the null hypothesis in favor of the alternative when α = .10 and .05. However,
we will fail to reject the null hypothesis when α = .01 and .001 since p-value = .0174 > .01.
if the sample mean is 1,241.2, sample standard deviation is s= 110.8 and the p-value testing H0
against Ha is 0.0174
Describe how much evidence we have that the new button's mean lifetime exceeds the mean
lifetime of the best remote button currently on the market correct answers With a p-value
of .0174, we conclude there is strong evidence that the mean lifetime of the new remote control
button is greater than 1200 hours.
Values of the standard normal random variable are measured: correct answers in the number of
standard deviations from the mean
This number is given by the z-table
The p-value for testing H0 versus Ha can be calculated to be 0.005,, Determine whether H0
would be rejected at each a= .10, .05, .01, and .001 correct answers A calculated p-value of 0.005
< 0.01, so we will reject the null hypothesis in favor of the alternative when α = 0.10, 0.05 and
0.01. However, we will fail to reject the null hypothesis when α = 0.001 since p-value = 0.005 >
0.001.
Consider a normal population with a mean of 10 and a variance of 4. find P (X>7) correct
answers z = (7 − 10)/√4 = −1.5
P(X > 7) = 1 − .0668 = .9332
Why do we need the z-score correct answers tells us how many standard deviations the value
falls from above or below the mean
-positive z-score: value x is ABOVE the mean
-negative z-score: value X is BELOW the mean
z-score table and formula correct answers z=(raw score-mean)/standard deviation
Confidence level correct answers the probability that the interval estimate will contain the
population parameter
, -DOES NOT MEAN probability that parameter will happen
The specific shape of each normal distribution is determined by its ______ and _______ correct
answers mean and standard deviation
-larger standard deviations make for longer curves while smaller standard deviations make for
taller curves.
Consider a normal population with a mean of 10 and a variance of 4. find P(X<6) correct
answers z = (6 − 10)/√4 = −2
P(X < 6) = .0228
______ values of the standards deviation result in a normal curve that is wider and flatter correct
answers larger
-The values are more spread out and further from the mean
The number of standard deviations that a value, x, is from the mean is a(an) _______ correct
answers z score
What is the probability that a standard normal random variable will be between .3 and 3.2 correct
answers P(.3 ≤ z ≤ 3.2) = .9993 − .6179 = .3814
Consider a normal population with a mean of 10 and a variance of 4. Find P(x≥10) correct
answers z = 0
P(z ≥ 0) = .5
An aptitude test has a mean score of 80 and a standard deviation of 5. The population of scores is
normally distributed. What proportion of tests has scores over 90? correct answers z=(90 − 80)/5
=2
p(X > 90) = 1 − .9772 = .0228
________ values of the standard deviation result in a normal curve that is narrower and more
peaked correct answers smaller
-the values are highly concentrated around the mean
What is the probability that a standard normal random variable will be between -2 and 2? correct
answers P(−2 ≤ z ≤ +2) = .9772 − .0228 = .9544
Properties of the normal probability distribution correct answers -The normal distribution is
symmetric
-The mean, median and mode are equal
-The area under the normal curve to the right of the mean is equal to the area under the normal
curve to the left of the mean.
-99.7% of all possible observed values of the random variable x are within plus or minus three
standard deviations of the population mean.
