Answer:
Therefore the required ways are =190
Step-by-step explanation:
Combination: Combination is the number of selection of items from a collection of items where the order of selection does not matter.
Total number of smartphones =22
Defective phone = 2
Non defective phone = (22-2) =20
The control inspector randomly test 4 smartphones of which 2 are defective.
Non defective phone = 2
The ways to select 2 non defective phone is

The ways to select 2 defective phone is= 
Therefore the required ways are = (190×1) =190
Answer: 35.675
Step-by-step explanation:
10.465−(−25.21)
The opposite of −25.21 is 25.21.
10.465+25.21
Add 10.465 and 25.21 to get 35.675.
35.675
To solve for the confidence interval for the population
mean mu, we can use the formula:
Confidence interval = x ± z * s / sqrt (n)
where x is the sample mean, s is the standard deviation,
and n is the sample size
At 95% confidence level, the value of z is equivalent to:
z = 1.96
Therefore substituting the given values into the
equation:
Confidence interval = 3 ± 1.96 * 5.8 / sqrt (51)
Confidence interval = 3 ± 1.59
Confidence interval = 1.41, 4.59
Therefore the population mean mu has an approximate range
or confidence interval from 1.41 kg to 4.59 kg.