### Answer to Question #100036 in Statistics and Probability for Tannah

# Answer to Question #100036 in Statistics and Probability for Tannah

**Category:
Answers>Math>Statistics and Probability **

A random sample of 128 firms was selected to investigate the average amount spent on liability insurance. The sample mean was found to be £25,500 per annum with a sample standard deviation equal to £3,250.

(i) Calculate the 95% confidence interval for the population mean.

(4 marks)

(ii) Calculate the 99% confidence interval for the population mean.

(4 marks)

(b) Discuss any four non probability sampling methods.

Here we have and i) Confidence interval is: Here, we have to find confidence interval, so Now, the value of Can be calculated using normal distribution table, which comes out to be So, the confidence interval will be ii) Confidence interval is: Here, we have to find confidence interval, so Now, the value of Can be calculated using normal distribution table, which comes out to be 2.58So, the confidence interval will be b) Non-probability sampling represents a group of sampling techniques that help researchers to select units from a population that they are interested in studying. Some of them are:Quota sampling: With proportional quota sampling, the aim is to end up with a sample where the strata (groups) being studied (e.g., males vs. females students) are proportional to the population being studied.Convenience sampling: A convenience sample is simply one where the units that are selected for inclusion in the sample are the easiest to access.Purposive sampling: Purposive sampling, also known as judgmental, selective or subjective sampling, reflects a group of sampling techniques that rely on the judgement of the researcher when it comes to selecting the units.Self selection sampling: Self-selection sampling is appropriate when we want to allow units or cases, whether individuals or organisations, to choose to take part in research on their own accord.