Answer:
Test:
< 20 with normal distⁿ
Hypothesis test:
H0:
20 (Null Hypothesis, H₀ :
= 20 is also correct)
H1:
< 20 (Alternative Hypothesis, also called H₁)
This is lower tailed test.
Since sample is large, sample standard deviation can be taken as an approximation of population standard deviation.
x = 19.3
= 11.1
n = 444
significance level,
= 0.05 (If no value is given, we take level of 0.05)
Test statistic


= - 1.33
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