Standard deviation - high school - practice problems - page 2 of 6
Number of problems found: 104
- Entrance exam
In a college entrance exam, the participants are rated as excellent, very good, good, and fair. Consider that the scores in the exam are normally distributed with a mean of 78 and a standard deviation of 7.5. The participants receiving the top 5% of the s - IQR and range
The times spent in minutes by 20 people waiting in a queue at the bank for a teller were: 3.4, 2.1, 3.8, 2.2, 4.5, 1.4, 0,0, 1.6, 4.8, 1.5, 1.9, 0, 3.6, 5.2, 2.7, 3.0, 0.8, 3.8, 5.2, Find the range and interquartile range of the waiting times. - Z score transformation
Suppose a distribution has a mean µ = 8 and standard deviation σ = 4. What is the value of x if it is z = +1.50? - Normally distributed
Suppose the height of male youngsters is normally distributed with a mean of 60 inches and a standard deviation of 10. what percentage of the boy's height would we expect to be between 44 and 75, less than 49, and 76 and more?
- The average 7
The average lifespan for cricket is 90 days, with a standard deviation of 13 days. If we assume that the lifespan of cricket is normally distributed, a. What is the probability a randomly selected cricket has a lifespan of fewer than 75 days? b. What is t - Dataset 3
Given dataset: 31, 28, 31,30,31,30,31,31,30,31,30,31 1. Construct a frequency table. 2. Construct a histogram. 3. Compute the mean. 4. Compute the median. 5. Find the mode. 6. Compute the midrange. 7. Compute the standard deviation. - Quartile statistics
Use the following data, which was obtained from a study of weights of adult men, to answer problems: Mean ; 192 lb ; First quartile ; 178lb Median; 185lb ; Third quartile ; 232 lb Mode ; 180 lb ; 86th percentile ; 239 lb Standard Deviation ; 23lb; ; a) Wh - Z-score test
The fish weights in a certain lake are normally distributed with a mean of 11 lb and a standard deviation of 6. If four fish are randomly selected, what is the probability that the mean weight will be between 8.6 and 14.6 lb? Your answer should be a decim - Summaries
A specialist teacher observes the time taken by each of the students with learning disabilities to complete a psychological task. She summaries the times using the following: Time Taken(mins) ; 1-5; 6-10; 11-12; 16-20 No. of Student ; 2 ; 4 ; 12; 4 Using
- A sample
A sample of 10 randomly selected students revealed the following grades in Business Statistics first test (on a marking scale of 0 to 100): 79, 63, 60, 45, 55, 58, 59, 62, 40, 68. Examine the data using groups and presenting: a) the Histogram of the absol - Suppose 6
Suppose the life span of a revolutionary light bulb is normally distributed with a mean life span of 70 thousand hours and a standard deviation of 3 thousand hours. If a light bulb is chosen at random: a) what is the probability the life span will be with - 10km race
Joan's finishing time for the bolder boulder 10 km race was 1.77 standard deviations faster than the women in her age group. 415 women ran in her age group. Assuming a normal distribution, how many women ran more quickly than Joan? - Z score transformation
The annual salary of an entry-level statistics major (in thousands of dollars) is normally distributed with a mean of 75 and a standard deviation of 12. X ∼ N ( μ = 75, σ = 12 ). What is the minimum salary a statistics major should aim for in order to ear - The probability
The probability that a life bulb will have a lifetime of more than 682 hours is 0.9788. The probability that a bulb will have a lifetime of more than 703 hours is 0.0051. Find the probability that a bulb will last for more than 648 hours.
- Two sigma
Khail took his math test and scored 88. If the class average was 78 with a standard deviation of 5, what percent of students earned a higher grade than Khail's grade? - A biologist
A biologist knows that the average length of a leaf of a certain plant is 4 inches. The standard deviation of the population is 0.6 inches. A sample of 20 leaves of that type of plant given a new type of plant food had an average length of 4.2 inches. At - An exam - normal distribution
Five thousand students take an exam with a mean of 59 and a deviation of 8. How many students will score less than 75? - The number 5
The number of hours per week the television is turned on is determined for each family in a sample. The mean of the data is 35 hours, and the median is 31.2 hours. Twenty-four families in the sample turned on the television for 20 hours or less for the we - Distribution 67074
The time required to complete the test has a normal distribution with a mean of 50 minutes and a standard deviation of 10 minutes. What percentage of students take the test within 30 minutes?
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