What is the standard deviation of the sample mean

Assignment Help Basic Statistics
Reference no: EM13247001

1. A study has shown that the interpupillary distance for all adult males is normally distributed with a mean of 65 mm and a standard deviation of 5 mm.

(1) What is the probability that the interpupillary distance for a randomly selected male will be between 64 and 67 mm?

(2) What is the probability that the mean interpupillary distance for a simple random sample of 25 males will be  between 64 and 67 mm?  What is the standard deviation of the sample mean here?

(3) What is the probability that the mean interpupillary distance for a simple random sample of 100 males will be  between 64 and 67 mm?  What is the standard deviation of the sample mean here?

(4) For each of the previous parts (a) through (c) of this question, indicate whether it is necessary to assume that interpupillary distance is normally distributed in order to arrive at an answer, and explain why.

2. For a population of 17 year old boys, the mean subscapular skinfold thickness is 9.7 mm and the standard deviation is 6.0 mm.  What is the probability that the mean skinfold thickness for a simple random sample of 40 boys will be (a) greater than 11 mm?, (b) no more than 7.5 mm?, (c) between 7 and 10.5 mm?, (d) within 1 mm of the mean?

3. Recall that when the empirical rule was discussed for X, it was argued that if X is exactly or approximately normal, then the probability that X will be within kσX of μ is given by P(μ - kσX £ X £ μ + kσX) = P(-k £ Z £ k).  Find the value of k such that the probability that X will be within kσX of μ is (a) 0.80, (b) 0.90, (c) 0.95, (d) 0.98, (e) 0.99.

Reference no: EM13247001

Questions Cloud

Express h in standard form for drawing a bode plot : Plot the Bode straight-line approximation phase plot (i.e., f(f) vs. f) for the transfer function over the range f = 10 rad/s to f = 100 krad/s using the 4-cycle semi-log graph paper provided. Label all slopes in degrees/dec and all levels in degr..
Calculate ni and the concentration of electrons and holes : An unknown semiconductor has Eg = 1.1 eV and Nc = Nv. It is doped with 10^15 cm^-3 donors where the donor level is 0.2 eV below Ec. Given that Ef is 0.25 eV below Ec, calculate ni and the concentration of electrons and holes in the semiconductor a..
Find atom in unstable state before it spontaneously decays : A sample of radiocactive material undergoes decay such that the number of atoms N(t) remaining in the unstable state at time t is related to the number No at t = 0 by the relation N(t) = No exp(t\tau)
How many atoms are found inside a unit cell of simple cubic : How many atoms are found inside a unit cell of a simple cubic, body-centered cubic, and faced-centered cubic crystal How far apart interms of lattice constant a are nearest neighbor atoms in each case, measured from center to center
What is the standard deviation of the sample mean : What is the probability that the interpupillary distance for a randomly selected male will be between 64 and 67 mm and What is the standard deviation of the sample mean
Write the test bench code to test the design : Write the verilog code for a circuit that counts the number of 1s in a byte. Write the verilog code using a structural approach based on four Half-Adders, two 2-bit adders and one 3-bit adder. Write the test bench code to test the design.
Calculate speed if load torque is reduced to three times : The DC shunt motor is running at full load with a supply voltage of 440 V and a supply current of 70 A. The rotation speed in full load is 1000 rpm, the field resistance is 200 Ohm and the armature resistance is 0.2 Ohm.
Write a matlab function for operation of a half-adder : Write a MATLAB function the performs the operation of a half-adder, call it half_add. The function should have two inputs, a and b, and return two outputs, X and c. Then, write another function, call it full_add, that invokes half_add to perform
Find the period of the orbit : An earth satellite is observed to have a height of pergee of 210 Kilometers and a height of apogee of 1,200 kilometers. Find the period of the orbit

Reviews

Write a Review

Basic Statistics Questions & Answers

  Fitting of orthogonal polynomial regression model

What conclusions can you draw about the nature of the relationship between anxiety and exam performance?

  Determining null hypothesis

A manufacturer wants to increase the absorption capacity of a sponge. Based on past data, the average sponge could absorb 3.5 ounces.

  Standard normal probability distribution

Let z be a standard normal random variable and calculate the following probabilities:

  Find the probability that none of the pencils are defective

In a sample batch of 46 mechanical pencils it is assumed that 18 are defective. If 5 mechanical pencils are randomly selected, what is the probability that none of them are defective?

  Determining poisson random variable

A manuscript is sent to a typing firm consisting of typists A, B, and C. If it is typed by A, then the number of errors made is a Poisson random variable with mean 2.6; if typed by B, then the number of errors is a Poisson random variable

  Find the critical value

Find the critical value having an area of 0.95 to its right for an F-curve with 8 numerator degrees of freedom and 15 denominator degrees of freedom.

  Hypothesis test-decision rule and test statistics

A consumer magazine randomly selected 100 new hybrid car dealers from across the country, and created a list of retail prices. They want to know if the price differs from $25,000.

  Probability problem on student recreation center

Based on past data, the Student Recreation Center knew that the proportion of students who prefer exercising outside over exercising in a gym was 0.734. To update their records, the SRC conducted a survey. Out of 95 students surveyed, 76 indicated..

  Estimate the probability of level for the companies fleet

Carbon monoxide (CO) emissions for a certain kind of car vary mean 2.4 g/mi and standard deviation 0.7g/mi. A company has 60 of these cars in its fleet. Let y represent the mean CO level for the companies fleet. Estimate the probability that y is ..

  Calculate the missing values in f ratio

Calculate the missing values in the following. The F ratio is = 5.00 between treatments SS DF Ms If withing treatments has a SS of 96, what is the degree of fredom and MS.

  Find probability that defective stereo came from company a

From Company B, 850 stereos are purchased and 6% are found to be defective. Given that a stereo is defective, find the probability that it came from Company A.

  Estimating the mean number of days of sick leave

A company is interested in estimating the mean number of days of sick leave taken by its employees. The firm's statistician randomly selects 100 personnel files and notes the number of sick days taken by each employee.

Free Assignment Quote

Assured A++ Grade

Get guaranteed satisfaction & time on delivery in every assignment order you paid with us! We ensure premium quality solution document along with free turntin report!

All rights reserved! Copyrights ©2019-2020 ExpertsMind IT Educational Pvt Ltd