Question

In: Statistics and Probability

. A researcher selects a random sample of 10 persons from a population of truck drivers...

. A researcher selects a random sample of 10 persons from a population of truck drivers and gives them a driver’s aptitude test. Their scores are 22,3,14,8,11,5,18,13,12, and 12.

     (a) Find the estimated standard error of the mean.

     (b) Find the 95% confidence interval for the population mean.

Solutions

Expert Solution

We have for given data,          
              
Sample mean =11.8      
Sample standard deviation =5.363  
Sample size =10     

a) Standard error of mean

=1.696


b)

Level of significance=0.05      
Degree of freedom =9      
              
t critical value is (by using t table)=2.262      
              
Confidence interval formula is               


=(7.96,15.64)          
              
              
Lower confidence limit=7.96  
              
Upper confidence limit= 15.64  

orchestra answered 2 years ago
Next > < Previous

Related Solutions

A researcher selects a sample of 100 participants from a population with a mean of 38...
A researcher selects a sample of 100 participants from a population with a mean of 38 and a standard deviation of 20. About 68% of the sample means in this sampling distribution should be between ______ and ______. Show your work
A researcher selects a sample of 49 participants from a population with a mean of 12...
A researcher selects a sample of 49 participants from a population with a mean of 12 and a standard deviation of 3.5. What is the probability of selecting a sample mean that is at least equal to the population mean? 0.50 equal to the probability of selecting a sample mean that is at most equal to the population mean all of the above none of the above
A researcher selects a sample of n=25 individuals from a population with a mean of μ=60...
A researcher selects a sample of n=25 individuals from a population with a mean of μ=60 and standard deviation of σ=10 and administers a treatment. The researcher predicts that the treatment will increase scores. Following the treatment, the average scores for this sample is M=65. 1. Using symbols, state the hypothesis for a one-tailed test. 2. Calculate the z-score and place this on a standardized normal distribution. 3. With a one-tail α=0.05, state the conclusion of these findings. 4. Calculate...
Question 27 options: A researcher selects a sample of n = 25 from a normal population...
Question 27 options: A researcher selects a sample of n = 25 from a normal population with µ = 80 and σ = 20. If the treatment is expected to increase scores by 6 points, what is the power of a two-tailed hypothesis test using α = .05? Enter the result for each step below: Step 1: Enter the standard error, σM (enter a number with 5 decimal places using only the keys "0-9" and "."): Step 2: Enter the...
A researcher selects 100 subjects at random from a population, observes 50 successes, and calculates three...
A researcher selects 100 subjects at random from a population, observes 50 successes, and calculates three confidence intervals. The confidence levels are 90%, 95%, and 99%, and the intervals are (0.402, 0.598), (0.371, 0.629), and (0.418, 0.582). Match each interval with its confidence level.
The grades of a sample of 10 applicants, selected at random from a large population, are...
The grades of a sample of 10 applicants, selected at random from a large population, are 71, 86, 75, 63, 92, 70, 81, 59, 80, and 90. Compute the sample variance. Can we infer at the 90% confidence that the population variance is significantly less than 100? (i.e. Perform Hypothesis testing)
A random sample of 49 measurements from one population had a sample mean of 10, with...
A random sample of 49 measurements from one population had a sample mean of 10, with sample standard deviation 3. An independent random sample of 64 measurements from a second population had a sample mean of 12, with sample standard deviation 4. Test the claim that the population means are different. Use level of significance 0.01. (a) What distribution does the sample test statistic follow? Explain. (b) State the hypotheses. (c) Compute x1 2 x2 and the corresponding sample test...
A random sample of sixty (60) long distance truck drivers were each asked if they often...
A random sample of sixty (60) long distance truck drivers were each asked if they often feel tired while driving. Forty five (45) of the truck drivers replied “yes”. (a) What is the sample proportion of long distance truck drivers who often feel tired while driving (two decimal places)? Type only the numeric answer in the box . The government introduced new laws requiring long distance truck drivers to take minimum rest breaks. Prior to introducing the new laws, the...
A random sample of sixty (60) long distance truck drivers were each asked if they often...
A random sample of sixty (60) long distance truck drivers were each asked if they often feel tired while driving. Forty five (45) of the truck drivers replied “yes”. (a) What is the sample proportion of long distance truck drivers who often feel tired while driving (two decimal places)? Type only the numeric answer in the box . The government introduced new laws requiring long distance truck drivers to take minimum rest breaks. Prior to introducing the new laws, the...
A random sample of n = 100 observations is drawn from a population with mean 10...
A random sample of n = 100 observations is drawn from a population with mean 10 and variance 400. (a) Describe the shape of the sampling distribution of ¯x. Does your answer depend on the sample size? ( b) Give the mean and standard deviation of the sampling distribution of ¯x. (c) Find the probability that ¯x is less than 8. (d) Find the probability that ¯x is greater than 9.5. (e) Find the probability that ¯x is between 8...
ADVERTISEMENT
Subjects
ADVERTISEMENT
Latest Questions
ADVERTISEMENT