Answer:
For x∈ {-∞,-3} y<0, below x-axis
x∈ {-3,-1} y>0, above x-axis
x∈ {-1,4} y<0, below x-axis
x∈ {4,∞} y>0, above x-axis
Step-by-step explanation:
f(x)=
=0
For x∈ {-∞,-3} y<0, below x-axis
x∈ {-3,-1} y>0, above x-axis
x∈ {-1,4} y<0, below x-axis
x∈ {4,∞} y>0, above x-axis
Answer:
The degrees of freedom are given by:
And the p value would be:
Since the p value is lower than the significance level we have enough evidence to reject the null hypothesis and we can conclude that the true mean is significantly higher than 2.3 ppm the safe limit
Step-by-step explanation:
Information provided
represent the sample mean in ppm
represent the sample standard deviation
sample size
represent the value to verify
represent the significance level
t would represent the statistic
represent the p value
System of hypothesis
We want to verify if the true mean is higher than 2,3 ppm, the system of hypothesis would be:
Null hypothesis:
Alternative hypothesis:
The statistic for this case is given by:
(1)
Replacing the info given we got:
The degrees of freedom are given by:
And the p value would be:
Since the p value is lower than the significance level we have enough evidence to reject the null hypothesis and we can conclude that the true mean is significantly higher than 2.3 ppm the safe limit