Eremy works two jobs. He makes $8/hr working at a deli and $12/hr working for a landscaper. Let x represent the number of hours
2 answers:
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Answer:
a) and
b) and
c)
d) and
Step-by-step explanation:
Part a
On this case the confidence is 87% or 0.87 so the significance level is and
. On this case we can assume that is a bilateral test or a confidence interval so we will have two critical values.
We need values a,b on the normal standard distribution such that:
or
and in order to find it we can use the following code in excel:
"NORM.INV(0.065,0,1)" or "NORM.INV(1-0.065,0,1)", and we see that the critical values and
Part b
On this case the confidence is 92% or 0.92 so the significance level is and
. On this case we can assume that is a bilateral test or a confidence interval so we will have two critical values.
First we need to calculate the degrees of freedom given by:
We need values b,c on the t distribution with 14 degrees of freddom such that:
or
and in order to find it we can use the following code in excel:
"T.INV(0.04,14)" or "T.INV(1-0.04,14)", and we see that the critical values and
Part c
The significance level is and is a left tailed test. On this case we know that is a left tailed test so then we have just one critical value.
First we need to calculate the degrees of freedom given by:
We need a value c on the t distribution with 17 degrees of freddom such that:
, and in order to find it we can use the following code in excel:
"T.INV(0.025,17)", and we see that the critical values
Part d
The significance level is and
. On this case we know that w ehave a two tailed proportion test, so we will have two critical values.
We need values a,b on the normal standard distribution such that:
or
and in order to find it we can use the following code in excel:
"NORM.INV(0.04,0,1)" or "NORM.INV(1-0.04,0,1)", and we see that the critical values and