9.
right tailed th populaton mean
10.
left tailed the population proportion
11.
two tailed the population standard deviation
12.
right tailed the population proportion
13.
left tailed the population mean
14.
two tailed the population standard deviation
15.
Ho: μ =.105
H1: μ > .105
type 1 error: you say the amount of births in the us to teen mothers is greater than 10.5% but in reality its not.
type 2: when you say the amount of births in the us to teen mothers is 10.5% but in reality its greater.
17.
Ho: μ = $218,600
H1: μ < $218,600
type 1: when you say the mean price is less than $218,600 for a single family home but in reality it isn’t.
type 2: when you say the mean price of a single family home is $218,600 but in reality its less.
19.
Ho: σ = 0.7 psi
H1: σ < 0.7 psi
type 1: when you say the standard deviation is less than 0.7 psi is less than 0.7 psi but in reality it isn’t
type 2: when you say the standard deviation is 0.7 psi but in reality its less.
21.
Ho: μ = $47.47
H1: μ ≠ $47.47
7.
9.
11.
13.
about 27 out of 100 samples will give a sample proportion as high or higher than the one obtained if the population proportion really is .5. this probability is not small so we do not reject he null. there is not enough evidence to conclude that the dart picking strategies resulted in a majority of winners.
15.
do not reject he null
no there is not enough evidence
17.
do not rejet the null
there is not enough evidence
19.
critical value = 1.64 test statistic = 2.65
we reject he null. there is not enough evidence.
1.
2.602
-1.729
2.179, -2.179
2.
1.321
2.426
2.738, -2.738
3.
-1.38
-1.714
Skip this problem.
no because -1.38 does not fall into the rejection region meaning its not unlikely
4.
2.67
1.318
Skip this problem.
yes because 2.67 is in the rejection region, meaning its too unlikely.
5.
2.5
2.819, -2.819
Skip this problem.
no the researcher will not reject the null because 2.5 is not too unlikely
(99.04, 110.56)
11.
Ho: μ = 67
the mean amount of money people withdraw from payease atm is $67
Ha: μ > 67
the mean amount of money people withdraw from payease atm is more than $67
There is a 0.02 probability of obtaining a sample mean of $73 or higher from a population whose mean is $67. So, if we obtained 100 simple random samples of size n = 40 from a population whose mean is $67, we would expect about 2 of these samples to result in sample means of $73 or higher.
Because the P-value is low (P@value = 0.02 6 a = 0.05), we reject the statement in the null hypothesis. There is sufficient evidence to conclude that the mean dollar amount withdrawn from a PayEase ATM is more than the mean amount from a standard ATM (that is, more than $67).
13.
Ho: μ = 22
the mean score on that math portion of the act is 22
Ha: μ > 22
the mean score on the math act is greater than 22
n = 200 is greater than 30
alpha is 0.05
we reject the null, so the mean acore on the math portion of the act is greater than a 22
15.
-4.55
we reject the null, so we believe the mean hippocampal volumes in alcoholic adolescents is less than 9.02 cm cubed
17.
.81
we do not reject the null. themean FICO score of high-income individuals is 703.5
19.
(35.44, 42.36)
the interval implies 40.7 is not too unlikely of an answer so we do not reject the null. there is not significant evidence to conclude that the mean age of a death-row inmate has changed since 2002.
1.
28.869
14.041
45.722, 16.047
3.
20.5
13.091
Skip this problem
no because 20.5 is not too unlikely of a value
x <- sd(c(108.5,80.4,67.4,95.5,58.0,86.3,75.9,70.9,65.1,72.0))
x## [1] 15.2050413.
Note. The sample standard deviation of the data shown is.\(15.205043\). You will have to knit this to see the number though.
18.2
we fail to reject the null. we believe the true standard deviation of wait times cars spend in the drive through at a fast food restuarant is is less than 18 seconds
15.
15.63
we do not reject the null. Derrick Rose’s consistency is not more than other NBA players.