# Life expectancy

The life expectancy of batteries has a normal distribution with a mean of 350 minutes and standard deviation of 10 minutes. What the range in minutes 68% of the batteries will last?
What is the range in minutes approximately 99.7% of batteries will last?

Result

a1 =  340 min
a2 =  360 min
b1 =  320 min
b2 =  380 min

#### Solution:    Leave us a comment of example and its solution (i.e. if it is still somewhat unclear...):

Showing 0 comments: Be the first to comment! #### To solve this example are needed these knowledge from mathematics:

Looking for help with calculating arithmetic mean? Looking for a statistical calculator? Looking for a standard deviation calculator?

## Next similar examples:

1. Water Mix 68 l of water with temperature of 87 °C, 17 l warm of 42 °C and 55 l water of 50 °C. What is the temperature of the mixed water immediately after mixing?
2. Angles in a triangle The angles of the triangle ABC make an arithmetic sequence with the largest angle γ=83°. What sizes have other angles in a triangle?
3. Team The football team has 11 players. Their average age is 20 years. During the match due to injury, one player withdraws and the average age of the team is 18. How old was injured player?
4. Daily average Calculate the average temperature during the day, when 13 hours was 22 °C and 11 hours was 17 °C.
5. RBA Regional Building Authority has an annual budget of EUR 1806814. In previous calendar year has processed 804 approval procedures. How much does an average of one building approval costs (eg unsuccessful revoke)?
6. Center Calculate the coordinates of the center of gravity T [x, y] of triangle ABC; A[11,4] B[13,-7] C[-17,-18].
7. Speed of Slovakian trains Rudolf decided to take the train from the station 'Trnava' to 'Zemianske Kostoľany'. In the train timetables found train R 725 Remata : km0Bratislava hl.st.12:574Bratislava-Vinohrady13:0113:0219Pezinok13:1213:1346Trnava13:3013:3263Leopoldov13:4514:0168H
8. Report card Ivor hit 4× grade 5 at the beginning of the school year. How many times must now catch grade 1 to get grade 2 on the report card?
9. Mailbox Mailbox is opening at regular intervals 3 times a day. The first time is opened at 8:00 and the last at 19:00. Calculate hours when mailbox is opened during day.
10. AVG of INT What is the average of the integers from 9 throuht 52 inclusive?
11. Balance The rod are 1.9 m long hanging weights 4 kg and 1 kg on ends. Where are centre of rod (distance from weight 4 kg) to be in balance?
12. Certificate There is 31 students in a class. From mathematics was'nt worse mark than 2. Average mark in mathematics was 2. How many students have mark 1 and how many mark 2?
13. Average What is the average speed of the car, where half of the distance covered passed at speed 66 km/h and the other half at 86 km/h.
14. Exam average Average of marks that have on the certificates students of 8.A class in mathematics is exactly 2.45. If we did not add 1 and 3 of sutdents Michael and Alena, who arrived a month ago, it would average exactly 2.5. Determine how many students have class 8.
15. Grandfather The grandfather is three years older than an grandmother. The average age of the grandmother, the grandfather and their seven grandchildren is 28 years. The grandchildren have a total of 105 years. Calculate how old is grandfather.
16. Enterprise and wages The enterprise operates a total 162 workers and their average salary is M dollars. If the company has hire an additional 18 employees whose average wage would be the S dollars, would reduce the overall average salary in the company of 3.6%. Calculate the
17. Railways - golden parachutes As often happens in Slovakia habit, the state's financial institution which takes from poverty and gorilas give. A hardworking punishing taxes. Let's look at a short work of director Railway Company ZSSK - Mgr . P. K. : 18 months 'work' as director .