The number of mosquitoes at the beach has increased by 50% every year since 2012. In 2012, there were 2,500 mosquitoes. How many
1 answer:
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Answer:
B) A one-sample t-test for population mean would be used.
Step-by-step explanation:
The complete question is shown in the image below.
The marketing executive is interested in comparing the mean number of sales of this year to that of previous year.
The marketing executive already has the value of mean from previous year and uses a sample to calculate the mean and standard deviation of sales for the current year.
Since, data is being collected for one sample only this limits us to chose between one sample test for mean. So now the possible options are one sample t-test for population mean and one sample t-test for population mean.
If we read the statement we can see that we have the value of sample mean and sample standard deviation. Value of population standard deviation is unknown. In cases where value of population standard deviation is not known and sample standard deviation is given, t-test is used.
Therefore, we can conclude that A one-sample t-test for population mean would be used.
Answer:
Possible lengths of the silk fibre 'x' are 100, 75, 60, 50 and 30 yards respectively.
Step-by-step explanation:
Let the length of the silk fiber = x yards.
Let the number of silk fibres = a.
It is given that the silk fibers between 3 to 10 yards are combined to form a silk thread of 300 yards.
So, we get the equation,
, where
i.e. ,
So, the possible values of 'a' are 3, 4, 5, 6 an 10.
Thus, the possible lengths of the silk fibre 'x' are 100, 75, 60, 50 and 30 yards respectively.