A box contains 100 Christmas light bulbs -- 40 green, 35 red and
25 blue. You randomly select two bulbs from the box with
replacement. The outcome of interest is the colour of each of the
two selected light bulbs. (a) List the complete sample space of
outcomes. (1 mark) (b) What is the probability that the two
selected bulbs are the same colour? (1 mark) (c) What is the
probability that the first selected bulb is green or that...
A metallurgist has invented a new tungsten alloy for use
in the filaments of light bulbs that is supposed to burn brighter
with the use of less energy. A company investigates the potential
costs of producing the new type of bulb and decides that production
would be economically feasible if the bulbs would last an average
of longer than 2000 hours in continuous usage. Twenty-five of the
new bulbs are tested and found to last an average of 2240 hours...
A company manufacturing light bulbs is testing a new model. The
company claims that the mean life time is less than 1000 hours.
A sample of 16 light bulbs are found to have sample mean of
987.5 hours and a sample variance of 400.
(a) Test this claim at the significance level α = 0.02.
Step 1:
Step 2:
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(b) Is there any assumption needed to solve this question? if
yes please state the...
A new LED light to replace incandescent bulbs has come on the
market. The box says it has an average life of 9,000 hours with a
standard deviation of 300 hours.
a) What is the probability that a single bulb will last between
8950 and 9100 hours?
b) What is the probability that the mean of a sample of 70 bulbs
picked at random will be between 8950 and 9100 hours?