Statistics
posted by George .
A maker of microwave ovens advertises that no more than 10% of its microwaves need repair during the first 5 years of use. In a random sample of 57 microwaves that are 5 years old, 13% needed repairs. At á=0.01, can you reject the maker’s claim that no more than 10% of its microwaves need repair during the first five years of use?

Null hypothesis:
Ho: p < or = .10 >meaning: population proportion is less than or equal to .10
Alternative hypothesis:
Ha: p > .10 >meaning: population proportion is greater than .10
Using a formula for a binomial proportion onesample ztest with your data included, we have:
z = .13  .10 / √[(.10)(.90)/57] >note: .90 represents 1  .10
Finish the calculation.
Use a ztable to find the critical or cutoff value at 0.01 for a onetailed test (upper tail). The test is onetailed because the alternative hypothesis is showing a specific direction (greater than).
If the ztest statistic calculated above exceeds the critical value from the ztable, reject the null. If the ztest statistic does not exceed the critical value from the ztable, do not reject the null.
I hope this will help get you started.
Respond to this Question
Similar Questions

physics....
Suppose that the inside length of a microwave oven is 30 cm. If the length of a microwave oven is one half of the wavelength of microwaves used by the oven, find the frequency of the microwaves used in the oven. What is the equation … 
chemistry 121
Microwave ovens use microwave radiation to heat food. The microwaves are absorbed by moisture in the food, which is transferred to other components of the food. As the water becomes hotter, so does the food. Suppose that the microwave … 
chemistry 121
Microwave ovens use microwave radiation to heat food. The microwaves are absorbed by moisture in the food, which is transferred to other components of the food. As the water becomes hotter, so does the food. Suppose that the microwave … 
chemistry
Your 1.1 cubic foot GE microwave oven generates 1100 watts of microwaves at a frequency of 2.45 GHz. a. What is the wavelength of the microwave radiation being emitted? 
Chemistry
microwave ovens work by irradiating food with microwaves, which is absorbed by the water molecules in the food and is converted into heat. Assuming that microwave ovens emit radiation with a wavelength of 12.2cm, calculate how many … 
chemistry
Microwaves are used to heat food in microwave ovens. The microwave radiation is absorbed by moisture in the food. This heats the water, and as the water becomes hot, so does the food. How many photons having a wavelength of 3.00 mm … 
physics
Microwave ovens typically cook food using microwaves the a frequency of about 3.00 GHz (gigahertz 10 to the nine Hz). Show the wavelength of these microwaves traveling at the speed of light is 10cm. 
Chemistry
Microwaves are used to heat food in microwave ovens. The microwave radiation is absorbed by moisture in the food. This heats the water, and as the water becomes hot, so does the food. How many photons having a wavelength of 3.00 mm … 
Chemistry
Microwave ovens heat food by creating microwave electromagnetic radiation that is absorbed by water molecules in the food. Any material that does not have water in it will not absorb the radiation and will not get hot. Metals reflect … 
statistics
A customer service division of a telecommunications firm receives 100 mobile phones for repair on a particular week. 18 of the phones are less than a year, 60 phones are more than a year but less than 2 years and the rest are older …