Answer:
a) The probability of obtaining a sample mean that is less than or equal to 1770 hours is P(M≤1770)=0.0013.
b) It is unusual, as there are only 13 chances in 10,000 (0.13%) of having this outcome.
Step-by-step explanation:
We have a population lifetime with mean of 1800 hours and standard deviation of 100 hours.
Samples of size n=100 are taken and tested.
We can calculate the probability of obtaining a sample mean that is less than or equal to 1770 hours using a z-score for the sample Mean M=1770 and then calculating its probability according to the standard normal distribution:
The Z-score is calculated by the formula below
Step 2: Substitute the given parameters in the formula
Hence, the z-score of a person who scored 145 on the exam is -0.5
It depends upon how many Staplers he buys
Answer:
150
Step-by-step explanation:
Rate at which volume decrease:
(1 × 2 × 20/100) ÷ 30
= 1/75 m³/min
Total volume:
½ × (1.4 + 0.6) × 2 × 1
= 2 m³
Time = 2 ÷ 1/75
= 150 mins
It’s a Yes, then No, then No