The video tutorial covers a survey conducted by Leona on customer visits to a shop. It explains how to calculate the probability of a customer visiting the shop five or more times and estimates the number of customers visiting exactly twice. The tutorial also discusses biased sampling in surveys, particularly when conducted at specific times, and concludes with an explanation of marks allocation for the questions.

What was the main focus of Leona's survey?

• The number of times customers visited the shop

• The average spending of customers

• The types of products purchased

• The customer satisfaction level

How many customers visited the shop 5 or more times?

• 13

• 35

• 29

• 24

What is the probability that a randomly chosen customer visited the shop 5 or more times?

• 0.35

• 0.13

• 0.24

• 0.29

How many customers visited the shop exactly 2 times last month, based on the survey?

• 130

• 150

• 210

• 195

Why might surveying customers after 9:00 AM lead to a biased sample?

• Elderly people do not shop in the morning

• Most people shop in the afternoon

• Children and working adults are less likely to be present

• The shop is less busy in the morning

What is a key requirement for obtaining an unbiased sample in a survey?

• Including a cross-section of all ages

• Focusing on a specific age group

• Conducting the survey over a weekend

• Surveying only during peak hours

What is a potential reason for a biased sample other than time of day?

• The location of the shop

• The weather conditions

• People's shopping habits

• The type of products sold