In detail: Based on the central limit theorem, the distribution appears normal due to the large sample size. The confidence interval is presented in the format: (Sample mean - margin of error, sample mean + margin of error). The sample mean, denoted as x, serves as the point estimate for the population mean. The confidence interval is computed as: mean ± z × σ/√n, where σ represents the population standard deviation. The formula transforms into confidence interval = x ± z × σ/√n, with specific values: x = $75, σ = $24. To find the z score, we subtract the confidence level from 100% which gives α as 1 - 0.96 = 0.04; halving this results in α/2 = 0.02, signifying the tail areas. To ensure we account for the center area, we have 1 - 0.02 = 0.98, corresponding to a z score of 2.05 for the 96% confidence level. The confidence interval becomes 75 ± 2.05 × 24/√64 = 75 ± 2.05 × 3 = 75 ± 6.15. The lower limit is 75 - 6.15 = 68.85, while the upper limit stands at 75 + 6.15 = 81.15. For n = 400, with x = $75 and σ = $24, the z score remains 2.05, resulting in the confidence interval calculated as 75 ± 2.05 × 24/√400 = 75 ± 2.05 × 1.2 = 75 ± 2.46. Subsequently, the lower bound becomes 75 - 2.46 = 72.54, and the upper limit adds up to 75 + 2.46 = 77.46. Lastly, when n = 400, x = $200, and σ = $80, the z score tied to a 94% confidence level is 1.88. Thus, the confidence interval is expressed as 200 ± 1.88 × 80/√400 = 200 ± 1.88 × 4 = 200 ± 7.52, giving us a margin of error of 7.52.
Answer:
The P-value ranges between 2.5% and 5% according to the t-table.
Step-by-step explanation:
A random sample of 16 students from a large university showed an average age of 25 years with a standard deviation of 2 years.
Let
= true average age of all students at the university.
So, the Null Hypothesis,
:
24 years {indicating the average age is less than or equal to 24 years}
Alternate Hypothesis,
:
> 24 years {indicating the average age is significantly greater than 24 years}
Here we employ the One-sample t-test statistics as the population's standard deviation is unknown;
T.S. =
~ 
where,
= sample average age = 25 years
s = sample standard deviation = 2 years
n = sample size = 16
This gives us the test statistics =
~
= 2
The value of the t-test statistics is 2.
Moreover, the P-value of the test-statistics can be found as follows;
P-value = P(
> 2) = 0.034 {as per the t-table}
Thus, the P-value lies between 2.5% and 5% based on the t-table.
A proportion maintains a consistent ratio m/d
If m = 0.75d, then the m/d ratio translates to (0.75d)/d = 0.75
In this case, the ratio can be expressed as (.75d-2)/d = 0.75 - (2/d).
Thus, it is not proportional.
The formula to calculate the difference between two standard deviations of populations n1 and n2 is:
sigma (difference)=√(sigma1/n1 + sigma2/n2). For this scenario:
sigma(d)= √(49/100 + 36/50)
Thus, the calculated standard deviation of the difference equals 1.1.