The line graph illustrates the average cost of a monthly contract for four different mobile phones in a European country between January and September in 2002, measured in euros.
Overall, it is clear that the monthly cost of Demo and Lex generally increased over the period, while Alpha’s price rose initially before declining in the second half of the period. Sim TX remained the cheapest option for most of the period, but its cost rose sharply in September, making it the most expensive of the four phones.
Regarding the Demo and Lex mobile phones, the Demo had the highest monthly cost in January, which stood at exactly 15 euros, but it had climbed marginally to exactly 20 euros in May. After one month of stable price, the figure rose noticeably to 25 euros in July, but then it declined by around 2 euros in September. The second highest monthly cost was held by Lex; it started at roughly 12 euros, followed by an insignificant fall of 2 euros. Then, the figure witnessed a steady growth, increasing from 10 euros to 18 euros with ups and downs between February and September.
In terms of Sim TX and Alpha, Sim TX had the lowest monthly payment, with exactly 5 euros in January. However, after having a one-month stable price, the figure increased slightly to about 7 euros in April. Interestingly, the marginal decline of 2 euros from April to June was seen in the cost of the monthly contract of Sim TX. In contrast, the figure overtook all other figures, reaching a peak of exactly 25 euros in September. When it comes to Alpha, the figure accounted for just under 10 euros, followed by a slight decrease to around 7 euros in February. Afterwards, it experienced a gradual rise to about 14 euros, from February to June, but then declined to roughly 7 euros by September.