Multiple choice: Normal distribution, Confidence Interval
Not what you're looking for?
1. The amount of pyridoxine (in grams) per multiple vitamin is normally distributed with m = 110 grams and Q(standard deviation)= 25 grams. A sample of 25 vitamins is to be selected. So, the middle 70% of all sample means will fall between what two values?
a) 104.8 and 115.2
b) 108.4 and 112.5
c) 115 and 100.7
d) 85 and 125
2. Which of the following about the normal distribution is not true?
a) Theoretically, the mean, median, and mode are the same.
b) About 2/3 of the observations fall within +,-1 standard deviation from the mean.
c) It is a discrete probability distribution.
d) Its parameters are the mean, m, and standard deviation, Q .
3. A major department store chain is interested in estimating the average amount its credit card customers spent on their first visit to the chain's new store in the mall.
Fifteen credit card accounts were randomly sampled and analyzed with the following results: X(sample mean)=$50.50 and S square=400. Construct a 95% confidence interval for the average amount its credit card customers spent on their first visit to the chain's new store in the mall.
a) $50.50+,- $9.09
b) $50.50+,- $10.12
c) $50.50+,- $11.00
d) $50.50+,- $11.08
I need detail explanation
Purchase this Solution
Solution Summary
Three Multiple choice questions on Normal distribution, Confidence Interval are answered.
Solution Preview
1. The amount of pyridoxine (in grams) per multiple vitamin is normally distributed with m = 110 grams and Q(standard deviation)= 25 grams. A sample of 25 vitamins is to be selected. So, the middle 70% of all sample means will fall between what two values?
a) 104.8 and 115.2
b) 108.4 and 112.5
c) 115 and 100.7
d) 85 and 125
Answer: a) 104.8 and 115.2
70% Confidence limits
We use z distribution as population standard deviation is given
Mean=μ= 110 garams
Standard deviation =σ= 25 garams
sample size=n= 25
σx=standard error of mean=σ/√n= 5 = ( 25 /√ 25)
Confidence level= 70%
Therefore Significance level=α= 30% =100% -70%
No of tails= 2
This is a 2 tailed test because we are calculating the confidence interval
Z at ...
Purchase this Solution
Free BrainMass Quizzes
Terms and Definitions for Statistics
This quiz covers basic terms and definitions of statistics.
Know Your Statistical Concepts
Each question is a choice-summary multiple choice question that presents you with a statistical concept and then 4 numbered statements. You must decide which (if any) of the numbered statements is/are true as they relate to the statistical concept.
Measures of Central Tendency
This quiz evaluates the students understanding of the measures of central tendency seen in statistics. This quiz is specifically designed to incorporate the measures of central tendency as they relate to psychological research.
Measures of Central Tendency
Tests knowledge of the three main measures of central tendency, including some simple calculation questions.