Statistics and Probability Answers

A SURVEY OF 100 RESPONDENTS WAS CONDUCTED TO STUDY PROPORTION PEOPLE SNORING IN THEIR SLEEP. Approximately 40% people claim that they do. Using this information, construct 90% confidence interval for the proportion of people that do snore in their sleep.

To investigate how often families camp in the summer, The Outdoorsman magazine surveyed 1,100 adults living with children under the age of 18. The survey results are shown in the table below.

he following are prices of a sanitizer sold at a few selected stores in a District A during the COVID-19 pandemic. Based on the sample data, at 0.05 level of significance, can we conclude the average price of the sanitizer in District A is RM25? Make your conclusion using the p-value approach, with the aid of Mic. Office EXCEL.

RM20.00, RM20.50, RM26.00, RM29.50, RM20.70, RM20.20, RM18.70, RM23.00 

Five computers will be delivered to a certain school for testing, but three of them are defective. The principal will get two of these computers for his office. Let T represent the random variable representing the defective computers will occur. Find the values of random variable T.  

There are 18 flights daily from Mumbai to Delhi of Go air, it is known that the probability that any flight arrives late is 0.25. a) what is the probability that one one of the flights is late today?

b) what is the average number of late flights? what is the variance of the number of late flights?

i) In a hotel, an intercom system master station provides music to six rooms. The probability that any one room will be switched on and draw power at anytime is 0.4. When on, a room draws 0.5 W.

What is the probability that the master station amplifier is overloaded, if the amplifier is overloaded when more than 2W is demanded?

ii) If the amplifier is replaced by a 4W unit which is supposed to supply 12 rooms now, then what would be the probability of its overload?

iii) If instead two independent 2W units are used to supply 6 rooms each, will the probability of the overload be better?

A study examined rates of posttraumatic stress disorder (PTSD) in mothers and fathers. Parents were interviewed 5 to 6 weeks after an accident or a new diagnosis of cancer or diabetes mellitus type I for their child. Twenty- eight of the 175 fathers interviewed and 43 of the 180 mothers interviewed met the criteria for current PTSD. Is there sufficient evidence for us to conclude that fathers are less likely to develop PTSD than mothers when a child is traumatized by an accident, cancer diagnosis, or diabetes diagnosis? Let α=5%.

Table 3 shows the selling price of a specific brand of sanitizer at five stores before and after the COVID-19 pandemic. At 0.1 level of confidence level, can we make a conclusion that on average, the price has not changed? Make your conclusion using the p-value approach, with the aid of Mic. Office EXCEL. Table 3

Before RM13.50 RM11.00 RM12.50 RM11.20 RM17.70

After RM13.50 RM12.00 RM12.50 RM11.20 RM18.80

(10 marks)

Table 4 shows the selling price of three different brands of sanitizer at based on 4 randomly selected supermarkets. At 80% confidence level, can we conclude there is a significant difference in mean price of the three brands of sanitizer? Make your conclusion using the p- value approach, with the aid of Mic. Office EXCEL.

Table 4

Brand A (in RM) Brand B Brand C

10.00 12.00 9.80

9.50 11.50 10.40

10.00 10.40 10.30

11.10 11.00 10.80

The following are prices of a sanitizer sold at a few selected stores in a District A during the COVID-19 pandemic. Based on the sample data, at 0.05 level of significance, can we conclude the average price of the sanitizer in District A is RM25? Make your conclusion using the p-value approach, with the aid of Mic. Office EXCEL.

RM20.00, RM20.50, RM26.00, RM29.50, RM20.70, RM20.20, RM18.70, RM23.00