A random sample of 12 graduates of a certain secretarial school typed an average of 79.3 words per minute with a standard deviation of 7.8 words per minute. assuming a normal distribution for the number of words typed per minute, find a 95% confidence interval for the average number of words typed by all graduates of this school.

Question

03-08-2017
Mathematics

contestada

A random sample of 12 graduates of a certain secretarial school typed an average of 79.3 words per minute with a standard deviation of 7.8 words per minute. assuming a normal distribution for the number of words typed per minute, find a 95% confidence interval for the average number of words typed by all graduates of this school.

Respuesta :

Otras preguntas

Read each group below. Then choose the letter of the item that contains a fragment. a. Because her cell phone had gone dead, Maria borrowed mine. Then she took

Compute the standard deviation if n = 60, p = 0.4, and the sample size is less than 10% of the population. A 0.04 B) 0.004 C) 0.002 D) 0.063

The trapezoid shown is divided into a right triangle and a rectangle.

What is the moment of highest tension in the story? A)Cameron's father tells her to clean her room.B)Cameron starts the stopwatch before cleaning the room.C)Ca

What type of chemical reaction is given by the following balanced equation: Al₂O3 → AL+ O₂

A rectangle is 15 cm wide and 18 cm long. If both dimensions are decreased by the same amount, the area of the new rectangle formed is 116 cm less than the area

Which revision correctly combines these two sentences? There was a lot of traffic today. It took an hour to get home. A. There was a lot of traffic today and it

What is the most likely meaning of the word earnest in this scene? Question 8 options: honest decitful rude a man's name

Which of the following do you advise the president to do? Be prepared to defend your answer. A. Ignore scientific developments and do not build an atomic bomb;

merlynthewhizz merlynthewhizz · Answer 1 · 2017-08-11T18:50:15+02:00

merlynthewhizz merlynthewhizz

11-08-2017

We will use the following formula to work out the confidence interval

Upper limit = μ + z* (σ/√n)
Lower limit = μ - z* (σ/√n)

We have
μ = 79.3
σ = 7.8
n = 12
z* is the z-score for 95% confidence level = 1.96

Substitute these into the formula, we have

Upper limit = 79.3 + 1.96 (7.8/√12) = 83.7
Lower limit = 79.3 - 1.96 )7.8/√12) = 74.9

Answer Link