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4/x=28/70 Pleaseeeee hwlpp
2 answers:
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Given:
μ = 25 mpg, the population mean
σ = 2 mpg, the population standard deviation
If we select n samples for evaluation, we should calculate z-scores that are based on the standard error of the mean.
That is,
The random variable is x = 24 mpg.
Part (i): n = 1
σ/√n = 2
z = (24 -25)/2 = -0.5
From standard tables,
P(x < 24) = 0.3085
Part (ii): n = 4
σ/√n = 1
z = (24 -25)/1 = -1
P(x < 24) = 0.1587
Part (iii): n=16
σ/√n = 0.5
z = (24 - 25)/0.5 = -2
P(x < 24) = 0.0228
Explanation:
The larger the sample size, the smaller the standard deviation.
Therefore when n increases, we are getting a result which is closer to that of the true mean.
μ = 25 mpg, the population mean
σ = 2 mpg, the population standard deviation
If we select n samples for evaluation, we should calculate z-scores that are based on the standard error of the mean.
That is,
The random variable is x = 24 mpg.
Part (i): n = 1
σ/√n = 2
z = (24 -25)/2 = -0.5
From standard tables,
P(x < 24) = 0.3085
Part (ii): n = 4
σ/√n = 1
z = (24 -25)/1 = -1
P(x < 24) = 0.1587
Part (iii): n=16
σ/√n = 0.5
z = (24 - 25)/0.5 = -2
P(x < 24) = 0.0228
Explanation:
The larger the sample size, the smaller the standard deviation.
Therefore when n increases, we are getting a result which is closer to that of the true mean.
Answer:
a) H0 : u = 28.5%
H1 : u < 28.5%
b) critical value = - 1.645
c) test statistic Z= - 1.41
d) Fail to reject H0
e) There is not enough evidence to support the professor's claim.
Step-by-step explanation:
Given:
P = 28.5% ≈ 0.285
X = 210
n = 800
Level of significance = 0.05
a) The null and alternative hypotheses are:
H0 : u = 28.5%
H1 : u < 28.5%
b) Given a 0.05 significance level.
This is a left tailed test.
The critical value =
The critical value = -1.645
c) Calculating the test statistic, we have:
Z = -1.41
d) Decision:
We fail to reject null hypothesis H0, since Z = -1.41 is not in the rejection region, <1.645
e) There is not enough evidence to support the professor's claim that the proportion of obese male teenagers decreased.