Answer:
6 7/12
Step-by-step explanation:
We need to get a common denominator, which is 12
12 1/4 - 5 2/3
12 1/4*3/3 - 5 2/3*4/4
12 3/12 - 5 8/12
We will need to borrow from the 12 since 3/12 is less than 8/12. Write the 1 we borrow as 12/12
11 + 12/12 + 3/12 - 5 8/12
11 15/12 - 5 8/12
6 7/12
Answer:
A) Population standard deviation is known.
B) Option 3
H0: μ =520,
H1: μ ≠ 520
z > 1.96 or z < -1.96
Step-by-step explanation:
A) The normal distribution should be used for the sample mean because the population standard deviation is known. Usually, when the standard deviation is unknown we don't use normal distribution except there is an underlying normal approximation.
B) Null Hypothesis:H0: μ =520,
Alternative hypothesis H1: μ ≠ 520
At 5% level of significance, from standard tables, we will reject H0 if;
The test statistic; z > 1.96 or z < -1.96
