Answer:The answer is D
Step-by-step explanation:
Answer:
about 3.9 lbs
Step-by-step explanation:
18 7/9 lbs - 14 7/8 lbs
convert mixed numbers to improper fractions
169/9 - 119/8
convert to common denominator
1352/72 - 1071/72
subtract numerators
281/72
about 3.9 lbs
Answer:
P = 0.0215 = 2.15%
Step-by-step explanation:
First we need to convert the values of 900 and 975 to standard scores using the equation:

Where z is the standard value, x is the original value,
is the mean and
is the standard deviation. So we have that:
standard value of 900: 
standard value of 975: 
Now, we just need to look at the standard distribution table (z-table) for the values of z = 2 and z = 3:
z = 2 -> p_2 = 0.9772
z = 3 -> p_3 = 0.9987
We want the interval between 900 and 975 hours, so we need the interval between z = 2 and z = 3, so we just need to subtract their p-values:
P = p_3 - p_2 = 0.9987 - 0.9772 = 0.0215
So the probability is 0.0215 = 2.15%
Answer: u= ( 4342.08, 5145.92).
Step-by-step explanation: the population mean is estimated using the sample by the formulae assuming a 95% confidence level
u = x' + Zα/2 * (√σ/n) or x' - Zα/2 * (√σ/n)
u = estimated population mean
x' = sample mean = 4744
n = sample size =8
σ = sample standard deviation. = 580
α = level of significance = 1- confidence level = 1-0.95= 0.05
Zα/2 = z score from the normal distribution table for a 2 tailed test = 1.96
First boundary value for interval
u = 4744 + 1.96 ( 580/√8)
u = 4744 + 1.96 * (205.0609)
u = 4744 + 401.92
u = 5145.92
Second boundary value for interval
u = 4744 - 1.96 ( 580/√8)
u = 4744 - 1.96 * (205.0609)
u = 4744 - 401.92
u = 4342.08
Thus the confidence interval for population mean is
u= ( 4342.08, 5145.92).