Videocassette Recorder (VCR) Tapes Are Designed So That Users Can

question 59

Essay

Videocassette recorder (VCR) tapes are designed so that users can repeatedly record new material over old material. However, after a number of re-recordings the tape begins to deteriorate. A VCR tape manufacturer is experimenting with a new technology, which hopefully will produce longer-lasting tapes. Thirty of the old-style tapes and 30 utilising the new technology were used in an experiment. The tapes were used to record and re-record programs until they began to deteriorate. The number of re-recordings is assumed to be normally distributed. It is generally accepted that the number of
re-recordings should exceed 55. Any tapes that do not meet this criterion are considered to be unacceptable. The number of re-recordings were observed and shown in the accompanying table. $$\begin{array} { | cc c |c c c | } \hline { \text { Old-style tapes } } &&& { \text { New-technology tapes } } \\\hline 60 & 61 & 48 & 68 & 70 & 58 \\\hline 51 & 46 & 66 & 74 & 72 & 69 \\\hline 66 & 63 & 61 & 77 & 73 & 49 \\\hline 73 & 55 & 71 & 59 & 66 & 61 \\\hline 71 & 49 & 76 & 52 & 58 & 59 \\\hline 47 & 56 & 55 & 66 & 51 & 49 \\\hline 60 & 62 & 64 & 62 & 59 & 57 \\\hline 52 & 51 & 63 & 51 & 56 & 66 \\\hline 64 & 68 & 52 & 50 & 55 & 76 \\\hline 47 & 55 & 58 & 63 & 68 & 78 \\\hline\end{array}$$ Determine whether these data are sufficient to infer at the 10% significance level that the two population variances differ.

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Definitions:

Alkaline

Having a pH greater than 7, typically describing a basic substance as opposed to an acidic one.

Humus

Organic component of soil formed by the decomposition of leaves and other plant material, rich in nutrients.

Deciduous Forest Soil

The fertile, nutrient-rich soil found in forests that lose their leaves seasonally, characterized by rich organic matter and biodiversity.

Closely Packed Pebbles

Small, smooth stones tightly grouped together, often found in riverbeds, beaches, or as a component of natural or humanmade surfaces.