Basic functions + mean - practice problems - page 2 of 9
Number of problems found: 168
- 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 - Final exam
There are five learners in a class that has written a final exam. Aleta scored 55%, Vera scored 36%, and Sibusiso scored 88%. If Thoko scored 71% and the class average was 63%. What was Davids's score as a percentage? - Corona virus
Calculate an estimate of the GDP (Gross Domestic Product) percentage that declined due to the quarantine related to the corona COVID-19 virus that lasted for two months. During this time, economic activity is down by 80%. - Mathematicians 11761
The top five mathematicians in the class took on the teacher's help calculating the paper's average grade. They dictated the following results: Mischa: "I came up with 3.30. " Dasha: "That's weird because it worked out precisely 3.45. " Jana: "You probabl
- N percentille problem
Here is a data set (n=117) that has been sorted. 10.4 12.2 14.3 15.3 17.1 17.8 18 18.6 19.1 19.9 19.9 20.3 20.6 20.7 20.7 21.2 21.3 22 22.1 22.3 22.8 23 23 23.1 23.5 24.1 24.1 24.4 24.5 24.8 24.9 25.4 25.4 25.5 25.7 25.9 26 26.1 26.2 26.7 26.8 27.5 27.6 2 - Average monthly salary
A total of 10 teachers work at one small school in Moravia. The monthly salary of each is 21,500 CZK or 21,800 CZK or 22,500 CZK, according to their education and age. The average monthly salary for this school's teacher is 21 850 CZK. How many teachers o - Unemployment rate
Over the last 16 years, the country's unemployment rate has changed according to the following frequency table: years of unemployment: 2 5 2 3 3 1 unemployment rate: 0.5 1 1.5 2 2.5 3 in % (percent). Determine the two-sided confidence interval for the var - Three sigma rule
The height of trees in a given stand is known to be a quantity with a normal probability distribution with a mean value of 15 m and a variance of 5 m². Determine the interval in which there will be tree heights in such a stand with a probability of 90% - Employees 4496
Four workshop workers had a basic hourly wage of € 8.50. Eight employees € 9.60, five employees € 10.90. What was the average basic hourly wage of workshop workers, and what will be if the hourly rates increase by 10%
- Enterprise and wages
The enterprise operates a total 162 workers, and their average salary is M dollars. If the company has hired an additional 18 employee whose average wage would be the S dollars, it will reduce the overall average salary by 3.6%. Calculate the value of the - Target
Peter, Martin, and Jirka were a fire in a particular target, with only three fields with values of 12, 18, and 30 points. All boys were firing with the same number of arrows, and all the arrows hit the target, and the results of every two boys differed by - 68-95-99.7 rule
Assume the resting pulse rates for a sample of individuals are normally distributed with a mean of 70 and a standard deviation of 15. Use the 68-95-99.7 rule to find the following quantities. a. Percentage of pulse rates less than 70 b. percentage of puls - Germination 55283
The supplier of spruce seeds for our nursery declares a germination rate of 80% for his goods. Verify this statement based on an experiment in which only 70 seeds germinated out of 100 randomly selected seeds. - Mathematics 7806
Janko has committed that his average grade in mathematics will be exactly 2 at the end of the semester. However, so far, he has received grades 3 and 4. He knows that by the end of the year, he will receive four more grades from the tests. What are the wo
- Test scores
Jo's test scores on the first four 100-point exams are as follows: 96,90,76, and 88. If all exams are worth the same percentage, what is the minimum test score necessary on his last exam to earn an A grade in the class (90% or better)? - Young mathematician
One young mathematician was bored again. He found that the average age of people in the room where the seminar equals its count. Then his 29-year-old brother entered the room. Even then, the average age of all present was the same as the count of people. - 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? - Jacob 2
Jacob took five summative tests in Mathematics during the first quarter, each with a maximum score of 100. Jacob's five integer test scores have a mean of 85, a median of 87, and a mode of 92. What is Jacob's lowest possible score from one of his five tes - Complaints
The table is given: days; complaints 0-4; 2 5-9; 4 10-14; 8 15-19; 6 20-24; 4 25-29; 3 30-34; 3 1.1 What percentage of complaints were resolved within two weeks? 1.2 calculate the mean number of days to resolve these complaints. 1.3 calculate the modal nu
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