Respuesta :
Answer:
H0:μ=440 g
Ha:μ does not equal 440 g
Step-by-step explanation:
kahn
The 90% confidence interval for the mean amount of pretzels per bag (in grams) in this production run for this case is [441.31, 458.69] approximately.
How to calculate confidence interval for population mean for small sample?
If the sample size is given to be n < 30, then for finding the confidence interval for mean of population from this small sample, we use t-statistic.
- Let the sample mean given as [tex]\overline{x}[/tex] and
- The sample standard deviation s, and
- The sample size = n, and
- The level of significance = [tex]\alpha[/tex]
Then, we get the confidence interval in between the limits
[tex]\overline{x} \pm t_{\alpha/2}\times \dfrac{s}{\sqrt{n}}[/tex]
where [tex]t_{\alpha/2}[/tex] is the critical value of 't' that can be found online or from tabulated values of critical value for specific level of significance and degree of freedom n - 1.
For this case, we're provided;
- The sample mean given as [tex]\overline{x}[/tex] = 450
- The sample standard deviation s = 15
- The sample size = n = 10
- The level of significance = [tex]\alpha[/tex] = 100 - 90% = 10% = 0.1
The critical value of t at level of significance 0.1 iand at degree of freedom 10-1=9 is:
Thus, the confidence interval in between the limits
[tex]450 \pm 1.833 \times \dfrac{15}{\sqrt{10}}[/tex]
or
[tex]450 \pm 8.69[/tex] approximately or 441.31 to 458.69 or we write it as: [441.31, 458.69] approximately.
Thus, the 90% confidence interval for the mean amount of pretzels per bag (in grams) in this production run for this case is [441.31, 458.69] approximately.
Learn more about confidence interval of population for small sample here:
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